Tsab xov xwm no yog ib feem ntawm lub ncauj lus tshawb fawb "Advanced bioremediation technologies and synthetic organic compounds (SOC) recycling processes". Saib tag nrho 14 tsab xov xwm.
Cov roj hydrocarbons uas muaj molecular weight tsawg (PAHs) xws li naphthalene thiab cov naphthalenes uas tau hloov (methylnaphthalene, naphthoic acid, 1-naphthyl-N-methylcarbamate, thiab lwm yam) yog siv dav hauv ntau yam lag luam thiab yog cov tshuaj lom rau cov kab mob genotoxic, mutagenic thiab/lossis carcinogenic rau cov kab mob. Cov organic compounds (SOCs) lossis xenobiotics no suav hais tias yog cov pa phem tseem ceeb thiab ua rau muaj kev hem thawj loj rau ib puag ncig thoob ntiaj teb thiab kev noj qab haus huv pej xeem. Qhov muaj zog ntawm tib neeg cov haujlwm (piv txwv li kev ua roj thee, kev ua roj refining, kev tso pa tawm ntawm tsheb thiab kev siv ua liaj ua teb) txiav txim siab qhov concentration, txoj hmoo thiab kev thauj mus los ntawm cov tshuaj ubiquitous thiab ruaj khov no. Ntxiv rau cov txheej txheem kho mob thiab tshuaj lom neeg, cov thev naus laus zis ntsuab thiab zoo rau ib puag ncig xws li bioremediation, uas siv cov kab mob me me uas muaj peev xwm ua rau POCs puas tsuaj tag nrho lossis hloov lawv mus rau hauv cov khoom tsis muaj tshuaj lom, tau tshwm sim ua lwm txoj hauv kev nyab xeeb, pheej yig thiab cog lus. Ntau hom kab mob uas yog cov phyla Proteobacteria (Pseudomonas, Pseudomonas, Comamonas, Burkholderia, thiab Neosphingobacterium), Firmicutes (Bacillus thiab Paenibacillus), thiab Actinobacteria (Rhodococcus thiab Arthrobacter) hauv cov av microbiota tau ua pov thawj tias muaj peev xwm rhuav tshem ntau yam organic compounds. Kev tshawb fawb txog metabolic, genomics, thiab metagenomic analysis pab peb nkag siab txog qhov nyuaj thiab ntau haiv neeg catabolic uas muaj nyob hauv cov qauv yooj yim no, uas tuaj yeem siv ntxiv rau kev rhuav tshem biodegradation zoo. Lub neej ntev ntawm PAHs tau ua rau muaj cov qauv rhuav tshem tshiab los ntawm kev hloov pauv gene kab rov tav siv cov ntsiab lus genetic xws li plasmids, transposons, bacteriophages, genomic islands, thiab integrative conjugative elements. Systems biology thiab genetic engineering ntawm cov isolates tshwj xeeb lossis cov zej zog qauv (consortia) tuaj yeem ua rau muaj kev kho mob bioremediation ntawm cov PAHs no los ntawm kev cuam tshuam synergistic. Hauv tsab xov xwm no, peb tsom mus rau ntau txoj kev sib txawv ntawm kev ua haujlwm ntawm lub cev thiab kev sib txawv ntawm cov noob caj noob ces, kev sib xyaw ua ke ntawm cov noob caj noob ces thiab kev sib txawv ntawm cov hlwb, thiab kev teb / kev hloov pauv ntawm cov hlwb ntawm naphthalene thiab cov kab mob uas ua rau cov naphthalene puas tsuaj. Qhov no yuav muab cov ntaub ntawv ecological rau kev siv hauv thaj teb thiab kev ua kom zoo dua qub rau kev kho cov kab mob kom zoo.
Kev loj hlob sai ntawm kev lag luam (petrochemicals, kev ua liaj ua teb, tshuaj, textile dyes, cosmetics, thiab lwm yam) tau pab txhawb kev vam meej ntawm kev lag luam thoob ntiaj teb thiab kev txhim kho cov qauv kev ua neej. Qhov kev loj hlob sai no tau ua rau muaj ntau cov khoom siv organic synthetic (SOCs), uas siv los tsim ntau yam khoom. Cov teb chaws txawv teb chaws lossis SOCs no suav nrog polycyclic aromatic hydrocarbons (PAHs), tshuaj tua kab, tshuaj tua kab, plasticizers, dyes, tshuaj, organophosphates, flame retardants, volatile organic solvents, thiab lwm yam. Lawv raug tso tawm mus rau hauv huab cua, dej thiab av ecosystems qhov twg lawv muaj ntau yam cuam tshuam, ua rau muaj kev cuam tshuam tsis zoo rau ntau yam bioforms los ntawm kev hloov pauv ntawm cov khoom physicochemical thiab cov qauv zej zog (Petrie et al., 2015; Bernhardt et al., 2017; Sarkar et al., 2020). Ntau yam tshuaj lom neeg uas muaj ntxhiab tsw qab muaj kev cuam tshuam loj heev thiab ua rau puas tsuaj rau ntau lub ecosystem / biodiversity hotspots (piv txwv li coral reefs, Arctic / Antarctic ice sheets, cov pas dej siab, cov av hauv dej tob, thiab lwm yam) (Jones 2010; Beyer et al. 2020; Nordborg et al. 2020). Cov kev tshawb fawb geomicrobiological tsis ntev los no tau qhia tias kev tso cov organic matter (piv txwv li aromatic pollutants) thiab lawv cov derivatives rau ntawm qhov chaw ntawm cov qauv cuav (ua ib puag ncig) (piv txwv li cov chaw keeb kwm kab lis kev cai thiab cov cim ua los ntawm granite, pob zeb, ntoo thiab hlau) ua rau lawv puas tsuaj sai dua (Gadd 2017; Liu et al. 2018). Tib neeg cov haujlwm tuaj yeem ua rau muaj kev puas tsuaj ntawm cov cim thiab cov tsev los ntawm kev ua pa phem thiab kev hloov pauv huab cua (Liu et al. 2020). Cov organic contaminations no react nrog dej vapor hauv huab cua thiab nyob rau ntawm cov qauv, ua rau lub cev thiab tshuaj lom neeg puas tsuaj ntawm cov khoom. Kev puas tsuaj ntawm cov khoom siv hauv lub cev (Biodegradation) yog qhov kev hloov pauv tsis zoo uas tshwm sim los ntawm cov kab mob uas cuam tshuam rau lawv txoj kev khaws cia (Pochon thiab Jaton, 1967). Kev ua haujlwm ntxiv ntawm cov kab mob me me (metabolism) ntawm cov tshuaj no tuaj yeem txo qhov kev ua haujlwm ntawm cov qauv, kev txuag tau zoo thiab kev coj noj coj ua (Gadd, 2017; Liu et al., 2018). Ntawm qhov tod tes, qee zaum, kev hloov kho microbial rau thiab teb rau cov qauv no tau pom tias muaj txiaj ntsig zoo vim lawv tsim cov biofilms thiab lwm cov tawv tiv thaiv uas txo qhov nrawm ntawm kev lwj / kev lwj (Martino, 2016). Yog li ntawd, kev tsim cov tswv yim txuag tau ntev rau cov pob zeb, hlau thiab ntoo monuments yuav tsum nkag siab zoo txog cov txheej txheem tseem ceeb uas koom nrog hauv cov txheej txheem no. Piv nrog cov txheej txheem ntuj (cov txheej txheem geological, hluav taws kub hav zoov, volcanic eruptions, cov nroj tsuag thiab cov kab mob), tib neeg cov haujlwm ua rau muaj kev tso tawm ntau ntawm polycyclic aromatic hydrocarbons (PAHs) thiab lwm yam organic carbon (OC) rau hauv ecosystems. Ntau cov PAHs siv hauv kev ua liaj ua teb (tshuaj tua kab thiab tshuaj tua kab xws li DDT, atrazine, carbaryl, pentachlorophenol, thiab lwm yam), kev lag luam (roj av nyoos, roj sludge/khib nyiab, roj av-ua los ntawm cov yas, PCBs, plasticizers, detergents, disinfectants, fumigants, tshuaj tsw qab thiab preservatives), cov khoom siv tu tus kheej (tshuaj pleev thaiv hnub, tshuaj tua kab, tshuaj tua kab thiab polycyclic musks) thiab cov mos txwv (tawg xws li 2,4,6-TNT) yog cov xenobiotics uas yuav cuam tshuam rau kev noj qab haus huv ntawm lub ntiaj teb (Srogi, 2007; Vamsee-Krishna thiab Phale, 2008; Petrie et al., 2015). Daim ntawv teev npe no tuaj yeem nthuav dav kom suav nrog cov khoom sib xyaw ua los ntawm roj av (roj roj, roj nplua nyeem, asphaltenes), cov bioplastics hnyav molecular, thiab cov kua ionic (Amde et al., 2015). Rooj 1 teev ntau yam tshuaj lom neeg aromatic thiab lawv cov ntawv thov hauv ntau yam lag luam. Nyob rau xyoo tas los no, cov pa phem ntawm cov organic uas tsis muaj zog, nrog rau cov pa roj carbon dioxide thiab lwm cov pa roj av uas ua rau lub tsev cog khoom, tau pib nce ntxiv (Dvorak et al., 2017). Txawm li cas los xij, cov kev cuam tshuam ntawm tib neeg ntau dua li cov ntuj tsim. Tsis tas li ntawd, peb pom tias muaj ntau qhov chaw nyob hauv ntau qhov chaw ib puag ncig thiab tau raug txheeb xyuas tias yog cov pa phem uas muaj cov teebmeem tsis zoo rau biomes (Daim Duab 1). Cov koom haum ib puag ncig xws li Lub Chaw Tiv Thaiv Ib Puag Ncig Tebchaws Meskas (USEPA) tau suav nrog ntau cov pa phem no hauv lawv daim ntawv teev npe tseem ceeb vim lawv cov khoom cytotoxic, genotoxic, mutagenic, thiab carcinogenic. Yog li ntawd, cov cai pov tseg nruj thiab cov tswv yim zoo rau kev kho / tshem tawm cov khib nyiab ntawm cov ecosystem uas muaj kuab paug yog qhov xav tau. Ntau txoj kev kho lub cev thiab tshuaj xws li pyrolysis, kev kho cua sov oxidative, cua aeration, landfilling, incineration, thiab lwm yam tsis muaj txiaj ntsig thiab kim thiab tsim cov khoom corrosive, lom thiab nyuaj rau kho. Nrog kev paub txog ib puag ncig thoob ntiaj teb nce ntxiv, cov kab mob me me uas muaj peev xwm ua rau cov pa phem no thiab lawv cov khoom siv (xws li halogenated, nitro, alkyl thiab / lossis methyl) tau nyiam kev saib xyuas ntau ntxiv (Fennell et al., 2004; Haritash thiab Kaushik, 2009; Phale et al., 2020; Sarkar et al., 2020; Schwanemann et al., 2020). Kev siv cov kab mob me me no ib leeg lossis hauv cov kab lis kev cai sib xyaw (cov pawg) rau kev tshem tawm cov pa phem aromatic muaj qhov zoo ntawm kev nyab xeeb ib puag ncig, tus nqi, kev ua haujlwm zoo, kev ua haujlwm zoo, thiab kev ruaj khov. Cov kws tshawb fawb kuj tseem tab tom tshawb nrhiav kev koom ua ke ntawm cov txheej txheem microbial nrog cov txheej txheem electrochemical redox, uas yog bioelectrochemical systems (BES), ua ib qho thev naus laus zis zoo rau kev kho / tshem tawm cov pa phem (Huang et al., 2011). BES thev naus laus zis tau nyiam kev saib xyuas ntau ntxiv vim nws qhov ua tau zoo, tus nqi qis, kev nyab xeeb ib puag ncig, kev ua haujlwm kub hauv chav, cov ntaub ntawv biocompatible, thiab lub peev xwm los rov qab tau cov khoom muaj nqis (piv txwv li, hluav taws xob, roj, thiab tshuaj lom neeg) (Pant et al., 2012; Nazari et al., 2020). Kev tshwm sim ntawm cov cuab yeej / cov txheej txheem genome sequencing siab thiab omics tau muab ntau cov ntaub ntawv tshiab ntawm kev tswj hwm caj ces, proteomics, thiab fluxomics ntawm cov tshuaj tiv thaiv ntawm ntau yam kab mob degrader. Kev sib xyaw ua ke ntawm cov cuab yeej no nrog cov kab ke biology tau txhim kho peb txoj kev nkag siab ntawm kev xaiv thiab kev kho kom zoo ntawm cov phiaj xwm catabolic hauv cov kab mob me me (piv txwv li, kev tsim qauv metabolic) kom ua tiav kev puas tsuaj biodegradation zoo thiab zoo. Txhawm rau tsim cov tswv yim bioremediation zoo siv cov kab mob me me uas tsim nyog, peb yuav tsum nkag siab txog lub peev xwm biochemical, kev sib txawv ntawm metabolic, cov qauv caj ces, thiab ecology (autoecology / synecology) ntawm cov kab mob me me.
Daim Duab 1. Cov chaw thiab txoj kev ntawm cov PAHs uas muaj cov molecular tsawg los ntawm ntau qhov chaw ib puag ncig thiab ntau yam uas cuam tshuam rau cov tsiaj txhu. Cov kab txiav ua kab sawv cev rau kev sib cuam tshuam ntawm cov ntsiab lus ntawm ecosystem.
Hauv tsab xov xwm no, peb tau sim sau cov ntaub ntawv txog kev puas tsuaj ntawm cov PAHs yooj yim xws li naphthalene thiab cov naphthalene hloov los ntawm ntau yam kab mob sib cais uas npog cov txheej txheem metabolic thiab kev sib txawv, cov enzymes koom nrog kev puas tsuaj, cov noob caj noob ces / cov ntsiab lus thiab kev sib txawv, cov lus teb ntawm tes thiab ntau yam ntawm bioremediation. Kev nkag siab txog cov biochemical thiab molecular theem yuav pab txheeb xyuas cov kab mob tswv tsev tsim nyog thiab lawv cov kev tsim kho caj ces ntxiv rau kev kho kom zoo ntawm cov pa phem tseem ceeb. Qhov no yuav pab tsim cov tswv yim rau kev tsim cov koom haum kab mob tshwj xeeb rau qhov chaw rau kev kho kom zoo.
Qhov muaj ntau cov tshuaj lom thiab txaus ntshai aromatic compounds (ua kom tau raws li Huckel txoj cai 4n + 2π electrons, n = 1, 2, 3, ...) ua rau muaj kev hem thawj loj rau ntau yam xov xwm ib puag ncig xws li huab cua, av, av noo, thiab saum npoo av thiab hauv av (Puglisi et al., 2007). Cov tshuaj no muaj ib lub nplhaib benzene (monocyclic) lossis ntau lub nplhaib benzene (polycyclic) teeb tsa hauv daim ntawv linear, angular lossis cluster thiab qhia txog kev ruaj khov (stability/instability) hauv ib puag ncig vim muaj zog resonance tsis zoo thiab inertness (inertness), uas tuaj yeem piav qhia los ntawm lawv cov hydrophobicity thiab txo qis lub xeev. Thaum lub nplhaib aromatic hloov ntxiv los ntawm methyl (-CH3), carboxyl (-COOH), hydroxyl (-OH), lossis sulfonate (-HSO3) pawg, nws ruaj khov dua, muaj kev sib raug zoo dua rau macromolecules, thiab yog bioaccumulative hauv biological systems (Seo et al., 2009; Phale et al., 2020). Qee cov roj carbon monoxide polycyclic aromatic (LMWAHs) uas tsis muaj molecular hnyav, xws li naphthalene thiab nws cov derivatives [methylnaphthalene, naphthoic acid, naphthalenesulfonate, thiab 1-naphthyl N-methylcarbamate (carbaryl)], tau suav nrog hauv daim ntawv teev cov organic pollutants tseem ceeb los ntawm US Environmental Protection Agency ua genotoxic, mutagenic, thiab/lossis carcinogenic (Cerniglia, 1984). Kev tso tawm ntawm cov chav kawm no ntawm NM-PAHs rau hauv ib puag ncig yuav ua rau muaj bioaccumulation ntawm cov tshuaj no ntawm txhua qib ntawm cov khoom noj khoom haus, yog li cuam tshuam rau kev noj qab haus huv ntawm ecosystems (Binkova et al., 2000; Srogi, 2007; Quinn et al., 2009).
Cov chaw thiab txoj kev ntawm PAHs mus rau biota feem ntau yog los ntawm kev tsiv teb tsaws chaw thiab kev sib cuam tshuam ntawm cov khoom sib txawv ntawm ecosystem xws li av, dej hauv av, dej saum npoo av, qoob loo thiab huab cua (Arey thiab Atkinson, 2003). Daim duab 1 qhia txog kev sib cuam tshuam thiab kev faib tawm ntawm cov PAHs qis molecular sib txawv hauv ecosystems thiab lawv txoj kev mus rau biota / tib neeg raug. PAHs raug tso rau ntawm qhov chaw vim yog huab cua ua pa phem thiab los ntawm kev tsiv teb tsaws chaw (drift) ntawm cov pa phem ntawm tsheb, cov pa roj tso tawm hauv kev lag luam (kev ua roj thee, kev sib xyaw thiab kev tsim coke) thiab lawv cov kev tso tawm. Cov haujlwm lag luam xws li kev tsim cov ntaub ua los ntawm cov khoom siv hluavtaws, cov xim thiab cov xim; kev khaws cia ntoo; kev ua roj hmab; kev tsim cov cement; kev tsim tshuaj tua kab; thiab kev siv ua liaj ua teb yog cov chaw tseem ceeb ntawm PAHs hauv cov kab ke hauv av thiab hauv dej (Bamforth thiab Singleton, 2005; Wick et al., 2011). Cov kev tshawb fawb tau qhia tias cov av hauv thaj chaw suburban thiab nroog loj, ze ntawm txoj kev loj, thiab hauv cov nroog loj muaj kev phom sij ntau dua rau polycyclic aromatic hydrocarbons (PAHs) vim yog cov pa phem los ntawm cov chaw tsim hluav taws xob, cua sov hauv tsev, huab cua thiab tsheb thauj mus los, thiab kev tsim kho (Suman et al., 2016). (2008) tau qhia tias PAHs hauv av ze ntawm txoj kev hauv New Orleans, Louisiana, Tebchaws Meskas yog siab txog 7189 μg/kg, thaum nyob rau hauv qhov chaw qhib, lawv tsuas yog 2404 μg/kg. Ib yam li ntawd, PAH theem siab txog 300 μg/kg tau tshaj tawm hauv thaj chaw ze ntawm cov chaw ua roj thee hauv ntau lub nroog hauv Tebchaws Meskas (Kanaly thiab Harayama, 2000; Bamforth thiab Singleton, 2005). Cov av los ntawm ntau lub nroog hauv Is Nrias teb xws li Delhi (Sharma et al., 2008), Agra (Dubey et al., 2014), Mumbai (Kulkarni thiab Venkataraman, 2000) thiab Visakhapatnam (Kulkarni et al., 2014) tau raug tshaj tawm tias muaj cov PAHs ntau heev. Cov tshuaj tsw qab yooj yim dua rau ntawm cov av, cov organic thiab cov av nplaum, yog li ua cov pa roj carbon loj hauv cov ecosystems (Srogi, 2007; Peng et al., 2008). Cov chaw tseem ceeb ntawm PAHs hauv cov ecosystems dej yog nag (ntub/qhuav nag thiab dej pa), dej ntws hauv nroog, dej khib nyiab tawm, dej hauv av rov qab los thiab lwm yam (Srogi, 2007). Kwv yees li ntawm 80% ntawm PAHs hauv cov ecosystems dej hiav txwv yog los ntawm nag, av noo, thiab dej khib nyiab tawm (Motelay-Massei et al., 2006; Srogi, 2007). Cov PAHs ntau dua hauv cov dej saum npoo av lossis cov dej tawm ntawm cov chaw pov tseg khib nyiab khov kho thaum kawg xau mus rau hauv av, ua rau muaj kev hem thawj loj rau kev noj qab haus huv pej xeem vim tias ntau dua 70% ntawm cov pej xeem hauv South thiab Southeast Asia haus cov dej hauv av (Duttagupta et al., 2019). Kev tshawb fawb tsis ntev los no los ntawm Duttagupta et al. (2020) ntawm cov dej ntws (32) thiab cov dej hauv av (235) kev tshuaj xyuas los ntawm West Bengal, Is Nrias teb, pom tias kwv yees li 53% ntawm cov neeg nyob hauv nroog thiab 44% ntawm cov neeg nyob deb nroog (tag nrho 20 lab tus neeg nyob) yuav raug rau naphthalene (4.9–10.6 μg/L) thiab nws cov khoom siv. Cov qauv siv av sib txawv thiab kev rho tawm dej hauv av ntau ntxiv raug suav hais tias yog cov yam tseem ceeb uas tswj kev thauj mus los ntsug (advection) ntawm cov PAHs qis molecular hauv av hauv av. Cov dej ntws los ntawm kev ua liaj ua teb, cov dej khib nyiab hauv nroog thiab kev lag luam, thiab cov khib nyiab khov kho / cov dej khib nyiab tau pom tias raug cuam tshuam los ntawm PAHs hauv cov hav dej thiab cov av hauv av. Cov nag los ntawm huab cua ua rau muaj kev ua qias tuaj ntawm PAH ntau ntxiv. Muaj cov PAHs ntau thiab lawv cov alkyl derivatives (tag nrho 51) tau tshaj tawm hauv cov dej/dej ntws thoob ntiaj teb, xws li Fraser River, Louan River, Denso River, Missouri River, Anacostia River, Ebro River, thiab Delaware River (Yunker et al., 2002; Motelay-Massei et al., 2006; Li et al., 2010; Amoako et al., 2011; Kim et al., 2018). Hauv cov av Ganges River basin, naphthalene thiab phenanthrene tau pom tias yog qhov tseem ceeb tshaj plaws (pom hauv 70% ntawm cov qauv) (Duttagupta et al., 2019). Ntxiv mus, kev tshawb fawb tau qhia tias chlorination ntawm dej haus tuaj yeem ua rau muaj cov pa oxygenated thiab chlorinated PAHs ntau dua (Manoli thiab Samara, 1999). Cov PAHs sib sau ua ke hauv cov nplej, txiv hmab txiv ntoo thiab zaub vim yog cov nroj tsuag nqus tau los ntawm cov av uas muaj kuab paug, dej hauv av thiab dej nag (Fismes et al., 2002). Ntau yam tsiaj txhu hauv dej xws li ntses, mussels, clams thiab cw muaj kuab paug nrog PAHs los ntawm kev noj cov zaub mov thiab dej hiav txwv uas muaj kuab paug, nrog rau los ntawm cov ntaub so ntswg thiab tawv nqaij (Mackay thiab Fraser, 2000). Cov txheej txheem ua noj/ua cov khoom noj xws li grilling, roasting, haus luam yeeb, kib, ziab, ci thiab ua noj nrog thee kuj tseem tuaj yeem ua rau muaj ntau PAHs hauv cov zaub mov. Qhov no feem ntau nyob ntawm kev xaiv cov khoom siv haus luam yeeb, cov ntsiab lus phenolic/aromatic hydrocarbon, cov txheej txheem ua noj, hom cua sov, cov ntsiab lus noo noo, cov pa oxygen thiab qhov kub ntawm kev sib xyaw (Guillén et al., 2000; Gomes et al., 2013). Polycyclic aromatic hydrocarbons (PAHs) kuj tau pom hauv mis nyuj ntawm ntau qhov sib txawv (0.75–2.1 mg/L) (Girelli et al., 2014). Qhov kev sib sau ua ke ntawm cov PAHs no hauv cov zaub mov kuj nyob ntawm cov khoom siv physicochemical ntawm cov zaub mov, thaum lawv cov teebmeem lom yog cuam tshuam nrog kev ua haujlwm ntawm lub cev, kev ua ub no ntawm cov metabolism, kev nqus, kev faib tawm thiab kev faib tawm ntawm lub cev (Mechini et al., 2011).
Qhov tshuaj lom thiab cov teebmeem tsis zoo ntawm polycyclic aromatic hydrocarbons (PAHs) tau paub ntev lawm (Cherniglia, 1984). Cov polycyclic aromatic hydrocarbons uas muaj qhov hnyav molecular tsawg (LMW-PAHs) (ob mus rau peb lub nplhaib) tuaj yeem khi rau ntau yam macromolecules xws li DNA, RNA thiab cov protein thiab yog carcinogenic (Santarelli et al., 2008). Vim lawv qhov xwm txheej hydrophobic, lawv raug sib cais los ntawm lipid membranes. Hauv tib neeg, cytochrome P450 monooxygenases oxidize PAHs rau epoxides, qee qhov yog reactive heev (piv txwv li, baediol epoxide) thiab tuaj yeem ua rau kev hloov pauv ntawm cov hlwb ib txwm mus rau hauv cov malignant (Marston et al., 2001). Tsis tas li ntawd, cov khoom hloov pauv ntawm PAHs xws li quinones, phenols, epoxides, diols, thiab lwm yam yog lom ntau dua li cov niam txiv sib xyaw. Qee cov PAHs thiab lawv cov tshuaj intermediates hauv kev ua haujlwm ntawm lub cev tuaj yeem cuam tshuam rau cov tshuaj hormones thiab ntau yam enzymes hauv kev ua haujlwm ntawm lub cev, yog li ntawd cuam tshuam tsis zoo rau kev loj hlob, lub paj hlwb hauv nruab nrab, lub cev yug me nyuam thiab lub cev tiv thaiv kab mob (Swetha thiab Phale, 2005; Vamsee-Krishna et al., 2006; Oostingh et al., 2008). Kev raug rau lub sijhawm luv luv rau cov PAHs uas muaj qhov hnyav molecular qis tau tshaj tawm tias ua rau lub ntsws ua haujlwm tsis zoo thiab thrombosis hauv cov neeg mob hawb pob thiab ua rau muaj kev pheej hmoo ntawm daim tawv nqaij, ntsws, zais zis thiab mob qog noj ntshav hauv plab (Olsson et al., 2010; Diggs et al., 2011). Kev tshawb fawb txog tsiaj kuj tau qhia tias kev raug PAH tuaj yeem muaj kev cuam tshuam tsis zoo rau kev ua haujlwm ntawm lub cev yug me nyuam thiab kev loj hlob thiab tuaj yeem ua rau mob cataracts, mob raum thiab siab, thiab mob jaundice. Ntau yam khoom siv PAH biotransformation xws li diols, epoxides, quinones thiab cov dawb radicals (cations) tau pom tias tsim cov DNA adducts. Cov adducts ruaj khov tau pom tias hloov cov tshuab DNA replication, thaum cov adducts tsis ruaj khov tuaj yeem depurinate DNA (feem ntau rau adenine thiab qee zaum rau guanine); ob qho tib si tuaj yeem tsim cov yuam kev uas ua rau mutations (Schweigert et al. 2001). Tsis tas li ntawd, quinones (benzo-/pan-) tuaj yeem tsim cov reactive oxygen species (ROS), ua rau puas tsuaj rau DNA thiab lwm yam macromolecules, yog li cuam tshuam rau cov ntaub so ntswg ua haujlwm / muaj sia nyob (Ewa thiab Danuta 2017). Kev raug rau cov pyrene, biphenyl thiab naphthalene tsawg tsawg tau tshaj tawm tias ua rau mob qog noj ntshav hauv cov tsiaj sim (Diggs et al. 2012). Vim lawv cov tshuaj lom tuag taus, kev ntxuav / tshem tawm cov PAHs no ntawm cov chaw cuam tshuam / muaj kuab paug yog qhov tseem ceeb.
Muaj ntau txoj kev siv lub cev thiab tshuaj lom neeg tau siv los tshem tawm PAHs ntawm cov chaw/ib puag ncig uas muaj kuab paug. Cov txheej txheem xws li kev hlawv, dechlorination, UV oxidation, fixation, thiab solvent extraction muaj ntau qhov tsis zoo, suav nrog kev tsim cov khoom lom, cov txheej txheem nyuaj, kev nyab xeeb thiab cov teeb meem kev cai, kev ua haujlwm qis, thiab tus nqi siab. Txawm li cas los xij, microbial biodegradation (hu ua bioremediation) yog lwm txoj hauv kev zoo uas cuam tshuam nrog kev siv cov kab mob me me hauv daim ntawv ntawm cov kab lis kev cai ntshiab lossis cov pawg neeg. Piv nrog rau cov txheej txheem lub cev thiab tshuaj lom neeg, cov txheej txheem no yog tus phooj ywg ib puag ncig, tsis muaj kev cuam tshuam, pheej yig, thiab ruaj khov. Bioremediation tuaj yeem ua tiav ntawm qhov chaw cuam tshuam (hauv situ) lossis ntawm qhov chaw npaj tshwj xeeb (ex situ) thiab yog li ntawd suav hais tias yog txoj hauv kev kho kom ruaj khov dua li cov txheej txheem lub cev thiab tshuaj lom neeg ib txwm muaj (Juhasz thiab Naidu, 2000; Andreoni thiab Gianfreda, 2007; Megharaj et al., 2011; Phale et al., 2020; Sarkar et al., 2020).
Kev nkag siab txog cov kauj ruam ntawm cov kab mob me me uas cuam tshuam nrog kev puas tsuaj ntawm cov pa phem muaj kev cuam tshuam loj heev rau kev tshawb fawb thiab kev lag luam rau kev ruaj khov ntawm ecological thiab ib puag ncig. Kwv yees li 2.1 × 1018 grams ntawm cov pa roj carbon (C) khaws cia rau hauv cov av thiab cov organic compounds (piv txwv li, roj, roj av, thiab thee, piv txwv li, roj fossil) thoob ntiaj teb, ua rau muaj kev pab tseem ceeb rau lub voj voog carbon thoob ntiaj teb. Txawm li cas los xij, kev lag luam sai, kev rho tawm roj fossil, thiab tib neeg cov haujlwm tab tom ua rau cov chaw khaws cia carbon lithospheric no ploj mus, tso tawm kwv yees li 5.5 × 1015 g ntawm cov pa roj carbon organic (ua cov pa phem) mus rau hauv huab cua txhua xyoo (Gonzalez-Gaya et al., 2019). Feem ntau ntawm cov pa roj carbon organic no nkag mus rau hauv av thiab marine ecosystems los ntawm kev tso dej, kev thauj mus los, thiab kev khiav tawm. Tsis tas li ntawd, cov pa phem tshiab uas tau los ntawm cov roj fossil, xws li yas, cov yas ua kom yas thiab cov yas ruaj khov (phthalates thiab lawv cov isomers), ua rau cov dej hiav txwv, av thiab cov ecosystems hauv dej thiab lawv cov biota ua rau muaj kev pheej hmoo ntawm huab cua thoob ntiaj teb. Ntau hom microplastics, nanoplastics, cov yas tawg thiab lawv cov khoom lom monomer uas tau los ntawm polyethylene terephthalate (PET) tau sib sau ua ke hauv Dej Hiav Txwv Pacific ntawm North America thiab Southeast Asia, tsim "Great Pacific Garbage Patch", ua rau cov tsiaj txhu hauv dej puas tsuaj (Newell et al., 2020). Kev tshawb fawb tau ua pov thawj tias nws tsis tuaj yeem tshem tawm cov pa phem / pov tseg los ntawm cov txheej txheem lub cev lossis tshuaj lom neeg. Hauv cov ntsiab lus no, cov kab mob me me uas muaj txiaj ntsig zoo tshaj plaws yog cov uas muaj peev xwm oxidatively metabolizing cov pa phem rau hauv carbon dioxide, lub zog tshuaj lom neeg thiab lwm yam khoom tsis muaj tshuaj lom uas thaum kawg nkag mus rau lwm cov txheej txheem nutrient cycling (H, O, N, S, P, Fe, thiab lwm yam). Yog li, kev nkag siab txog microbial ecophysiology ntawm aromatic pollutant mineralization thiab nws txoj kev tswj hwm ib puag ncig yog qhov tseem ceeb rau kev ntsuas lub voj voog microbial carbon, cov peev nyiaj net carbon thiab kev pheej hmoo huab cua yav tom ntej. Vim muaj qhov xav tau ceev ceev kom tshem tawm cov tshuaj no ntawm ib puag ncig, ntau yam kev lag luam eco-tsom mus rau cov thev naus laus zis huv tau tshwm sim. Lwm txoj kev, kev muab cov khib nyiab hauv kev lag luam / cov tshuaj pov tseg uas tau khaws cia rau hauv cov ecosystem (piv txwv li cov khib nyiab mus rau kev nplua nuj) yog suav hais tias yog ib qho ntawm cov hauv paus ntawm kev lag luam ncig thiab lub hom phiaj kev txhim kho kom ruaj khov (Close et al., 2012). Yog li ntawd, kev nkag siab txog cov yam ntxwv ntawm kev ua haujlwm ntawm lub cev, enzymatic thiab genetic ntawm cov neeg sib tw ua rau muaj kev puas tsuaj no yog qhov tseem ceeb tshaj plaws rau kev tshem tawm thiab kev kho cov pa phem uas muaj ntxhiab tsw qab.
Ntawm ntau yam tshuaj lom neeg uas muaj ntxhiab tsw qab, peb tau them sai sai rau cov PAHs uas tsis muaj molecular hnyav xws li naphthalene thiab cov naphthalene hloov. Cov tshuaj no yog cov khoom tseem ceeb ntawm cov roj av, cov xim pleev xim rau ntaub, cov khoom siv rau cov neeg siv khoom, cov tshuaj tua kab (cov npauj npaim thiab cov tshuaj tua kab), cov yas ua kom zoo nkauj thiab cov tannins thiab yog li ntawd dav dav hauv ntau lub ecosystem (Preuss et al., 2003). Cov ntawv ceeb toom tsis ntev los no qhia txog kev sib sau ua ke ntawm cov naphthalene hauv cov av dej, cov av hauv av thiab cov av hauv av, cov cheeb tsam vadose thiab cov txaj dej, qhia txog nws cov bioaccumulation hauv ib puag ncig (Duttagupta et al., 2019, 2020). Rooj 2 qhia txog cov khoom siv physicochemical, kev siv thiab cov teebmeem kev noj qab haus huv ntawm naphthalene thiab nws cov derivatives. Piv nrog rau lwm cov PAHs uas muaj cov molecular hnyav, naphthalene thiab nws cov derivatives yog cov hydrophobic tsawg dua, yaj tau dej ntau dua thiab faib dav hauv ecosystems, yog li lawv feem ntau siv ua cov qauv substrates los kawm txog kev ua haujlwm ntawm lub cev, noob caj noob ces thiab kev sib txawv ntawm cov metabolism ntawm PAHs. Muaj ntau cov kab mob me me uas muaj peev xwm ua haujlwm ntawm naphthalene thiab nws cov derivatives, thiab cov ntaub ntawv qhia txog lawv cov kev ua haujlwm ntawm lub cev, cov enzymes thiab cov yam ntxwv tswj hwm (Mallick et al., 2011; Phale et al., 2019, 2020). Tsis tas li ntawd, naphthalene thiab nws cov derivatives raug xaiv los ua cov tshuaj prototype rau kev ntsuam xyuas kev ua qias tuaj ib puag ncig vim lawv muaj ntau thiab bioavailability. Lub Koom Haum Tiv Thaiv Ib Puag Ncig ntawm Tebchaws Meskas kwv yees tias qhov nruab nrab ntawm naphthalene yog 5.19 μg ib lub cubic meter los ntawm cov pa luam yeeb, feem ntau los ntawm kev hlawv tsis tiav, thiab 7.8 txog 46 μg los ntawm cov pa luam yeeb sab, thaum raug rau creosote thiab naphthalene yog 100 txog 10,000 npaug siab dua (Preuss et al. 2003). Tshwj xeeb tshaj yog, naphthalene tau pom tias muaj kev lom rau cov tsiaj txhu, thaj chaw, thiab poj niam txiv neej thiab ua rau mob qog noj ntshav. Raws li kev tshawb fawb txog tsiaj txhu, Lub Chaw Haujlwm Thoob Ntiaj Teb rau Kev Tshawb Fawb Txog Kab Mob Cancer (IARC) tau faib naphthalene ua "ua rau mob qog noj ntshav rau tib neeg" (Pawg 2B)1. Kev raug cov tshuaj naphthalene hloov, feem ntau yog los ntawm kev nqus pa lossis kev tswj hwm (qhov ncauj), ua rau cov nqaij ntsws raug mob thiab ua rau muaj qog nqaij ntsws ntau ntxiv rau cov nas thiab nas (National Toxicology Program 2). Cov teebmeem mob hnyav suav nrog xeev siab, ntuav, mob plab, raws plab, mob taub hau, tsis meej pem, hws ntau, kub taub hau, tachycardia, thiab lwm yam. Ntawm qhov tod tes, cov tshuaj tua kab carbamate dav dav carbaryl (1-naphthyl N-methylcarbamate) tau tshaj tawm tias muaj tshuaj lom rau cov tsiaj txhu hauv dej, cov tsiaj amphibians, cov muv zib ntab thiab tib neeg thiab tau pom tias inhibit acetylcholinesterase ua rau tuag tes tuag taw (Smulders et al., 2003; Bulen thiab Distel, 2011). Yog li ntawd, kev nkag siab txog cov txheej txheem ntawm kev puas tsuaj ntawm cov kab mob me me, kev tswj hwm caj ces, kev ua haujlwm enzymatic thiab cellular yog qhov tseem ceeb rau kev tsim cov tswv yim bioremediation hauv cov chaw muaj kuab paug.
Rooj 2. Cov ntaub ntawv qhia txog cov khoom siv thiab tshuaj lom neeg ntawm naphthalene thiab nws cov khoom siv.
Hauv cov niches uas muaj kuab paug, cov pa phem hydrophobic thiab lipophilic aromatic tuaj yeem ua rau muaj ntau yam teebmeem ntawm tes rau ntawm cov microbiome ib puag ncig (lub zej zog), xws li kev hloov pauv ntawm cov kua membrane, cov permeability ntawm daim nyias nyias, lipid bilayer o, kev cuam tshuam ntawm kev hloov pauv zog (cov saw hlau thauj hluav taws xob / proton motive force), thiab kev ua haujlwm ntawm cov protein cuam tshuam nrog daim nyias nyias (Sikkema et al., 1995). Tsis tas li ntawd, qee cov tshuaj nruab nrab uas yaj tau xws li catechols thiab quinones tsim cov tshuaj reactive oxygen (ROS) thiab tsim cov adducts nrog DNA thiab cov protein (Penning et al., 1999). Yog li, qhov muaj ntau ntawm cov tshuaj no hauv ecosystems ua rau muaj kev xaiv siab rau cov zej zog microbial kom dhau los ua cov khoom siv degradable ntawm ntau qib kev ua haujlwm, suav nrog kev nqus / kev thauj mus los, kev hloov pauv hauv lub hlwb, kev sib sau ua ke / kev siv, thiab kev faib ua pawg.
Kev tshawb nrhiav ntawm Ribosomal Database Project-II (RDP-II) tau qhia tias tag nrho 926 hom kab mob tau raug rho tawm los ntawm cov xov xwm lossis cov kab lis kev cai nplua nuj uas muaj naphthalene lossis nws cov khoom siv. Pawg Proteobacteria muaj cov neeg sawv cev ntau tshaj plaws (n = 755), ua raws li Firmicutes (52), Bacteroidetes (43), Actinobacteria (39), Tenericutes (10), thiab cov kab mob tsis raug cais tawm (8) (Daim Duab 2). Cov neeg sawv cev ntawm γ-Proteobacteria (Pseudomonadales thiab Xanthomonadales) tau tswj hwm txhua pawg Gram-negative nrog cov ntsiab lus G+C siab (54%), thaum Clostridiales thiab Bacillales (30%) yog pawg Gram-positive nrog cov ntsiab lus G+C qis. Cov kab mob Pseudomonas (tus lej siab tshaj plaws, 338 hom) tau tshaj tawm tias muaj peev xwm rhuav tshem naphthalene thiab nws cov methyl derivatives hauv ntau yam ecosystem uas muaj kuab paug (xws li thee tar, roj av, roj nyoos, sludge, roj nchuav, dej khib nyiab, organic pov tseg thiab cov chaw pov tseg) nrog rau hauv cov ecosystem uas tseem muaj (av, dej ntws, av noo thiab dej hauv av) (Daim Duab 2). Ntxiv mus, kev tshawb fawb txog kev nplua nuj thiab kev tshuaj xyuas metagenomic ntawm qee thaj chaw no tau qhia tias cov kab mob Legionella thiab Clostridium uas tsis tau cog qoob loo yuav muaj peev xwm rhuav tshem, qhia txog qhov xav tau kev cog qoob loo cov kab mob no los kawm txog txoj hauv kev tshiab thiab kev sib txawv ntawm cov metabolism.
Daim Duab 2. Kev sib txawv ntawm cov kab mob thiab kev faib tawm ntawm cov kab mob hauv cov chaw muaj kuab paug nrog naphthalene thiab naphthalene derivatives.
Ntawm ntau yam kab mob me me uas ua rau cov pa roj carbon dioxide puas tsuaj, feem ntau muaj peev xwm ua rau naphthalene puas tsuaj ua qhov chaw tsuas yog muab cov pa roj carbon thiab lub zog xwb. Cov xwm txheej uas cuam tshuam nrog kev ua haujlwm ntawm naphthalene tau piav qhia rau Pseudomonas sp. (cov kab mob: NCIB 9816-4, G7, AK-5, PMD-1 thiab CSV86), Pseudomonas stutzeri AN10, Pseudomonas fluorescens PC20 thiab lwm cov kab mob (ND6 thiab AS1) (Mahajan et al., 1994; Resnick et al., 1996; Annweiler et al., 2000; Basu et al., 2003; Dennis thiab Zylstra, 2004; Sota et al., 2006; Metabolism yog pib los ntawm ntau yam dioxygenase [naphthalene dioxygenase (NDO), lub nplhaib hydroxylating dioxygenase] uas catalyzes qhov oxidation ntawm ib qho ntawm cov nplhaib aromatic ntawm naphthalene siv cov pa oxygen molecular ua lwm lub substrate, hloov naphthalene rau cis-naphthalenediol (Daim Duab 3). Cis-dihydrodiol yog hloov mus rau 1,2-dihydroxynaphthalene los ntawm ib qho dehydrogenase. Ib qho dioxygenase uas tawg ua lub nplhaib, 1,2-dihydroxynaphthalene dioxygenase (12DHNDO), hloov 1,2-dihydroxynaphthalene mus rau 2-hydroxychromene-2-carboxylic acid. Enzymatic cis-trans isomerization tsim cov trans-o-hydroxybenzylidenepyruvate, uas yog hydratase aldolase cleaved mus rau salicylic aldehyde thiab pyruvate. Cov organic acid pyruvate yog thawj C3 compound uas tau los ntawm naphthalene carbon skeleton thiab coj mus rau hauv txoj kev carbon nruab nrab. Tsis tas li ntawd, NAD+-dependent salicylaldehyde dehydrogenase hloov salicylaldehyde mus rau salicylic acid. Metabolism ntawm theem no hu ua "txoj kev sab saud" ntawm naphthalene degradation. Txoj kev no yog qhov tshwm sim ntau heev hauv feem ntau cov kab mob naphthalene-degrading. Txawm li cas los xij, muaj ob peb qhov kev zam; piv txwv li, hauv thermophilic Bacillus hamburgii 2, naphthalene degradation yog pib los ntawm naphthalene. 2,3-dioxygenase los ua 2,3-dihydroxynaphthalene (Annweiler li al., 2000).
Daim Duab 3. Txoj Kev ntawm naphthalene, methylnaphthalene, naphthoic acid, thiab carbaryl degradation. Cov lej voj voog sawv cev rau cov enzymes uas muaj lub luag haujlwm rau kev hloov pauv ntawm naphthalene thiab nws cov derivatives mus rau hauv cov khoom tom ntej. 1 — naphthalene dioxygenase (NDO); 2, cis-dihydrodiol dehydrogenase; 3, 1,2-dihydroxynaphthalene dioxygenase; 4, 2-hydroxychromene-2-carboxylic acid isomerase; 5, trans-O-hydroxybenzylidenepyruvate hydratase aldolase; 6, salicylaldehyde dehydrogenase; 7, salicylate 1-hydroxylase; 8, catechol 2,3-dioxygenase (C23DO); 9, 2-hydroxymuconate semialdehyde dehydrogenase; 10, 2-oxopent-4-enoate hydratase; 11, 4-hydroxy-2-oxopentanoate aldolase; 12, acetaldehyde dehydrogenase; 13, catechol-1,2-dioxygenase (C12DO); 14, muconate cycloisomerase; 15, muconolactone delta-isomerase; 16, β-ketoadipatenollactone hydrolase; 17, β-ketoadipate succinyl-CoA transferase; 18, β-ketoadipate-CoA thiolase; 19, succinyl-CoA: acetyl-CoA succinyltransferase; 20, salicylate 5-hydroxylase; 21 – gentisate 1,2-dioxygenase (GDO); 22, maleylpyruvate isomerase; 23, fumarylpyruvate hydrolase; 24, methylnaphthalene hydroxylase (NDO); 25, hydroxymethylnaphthalene dehydrogenase; 26, naphthaldehyde dehydrogenase; 27, 3-formylsalicylic acid oxidase; 28, hydroxyisophthalate decarboxylase; 29, carbaryl hydrolase (CH); 30, 1-naphthol-2-hydroxylase.
Nyob ntawm seb tus kab mob thiab nws cov noob caj ces, cov salicylic acid uas tshwm sim los ntawm kev hloov pauv ntxiv los ntawm txoj kev catechol siv salicylate 1-hydroxylase (S1H) lossis los ntawm txoj kev gentisate siv salicylate 5-hydroxylase (S5H) (Daim Duab 3). Vim tias salicylic acid yog qhov tseem ceeb hauv kev hloov pauv naphthalene (txoj kev sab saud), cov kauj ruam los ntawm salicylic acid mus rau TCA intermediate feem ntau hu ua txoj kev qis dua, thiab cov noob caj ces tau teeb tsa ua ib qho operon. Nws yog ib qho uas pom tias cov noob caj ces hauv txoj kev sab saud operon (nah) thiab txoj kev qis dua operon (sal) raug tswj hwm los ntawm cov yam ntxwv tswj hwm; piv txwv li, NahR thiab salicylic acid ua haujlwm ua inducers, tso cai rau ob qho operons kom hloov pauv naphthalene tag nrho (Phale et al., 2019, 2020).
Ntxiv rau, catechol raug cyclically cleaved rau 2-hydroxymuconate semialdehyde ntawm txoj kev meta los ntawm catechol 2,3-dioxygenase (C23DO) (Yen et al., 1988) thiab ntxiv hydrolyzed los ntawm 2-hydroxymuconate semialdehyde hydrolase los tsim 2-hydroxypent-2,4-dienoic acid. 2-hydroxypent-2,4-dienoate ces hloov mus rau pyruvate thiab acetaldehyde los ntawm hydratase (2-oxopent-4-enoate hydratase) thiab aldolase (4-hydroxy-2-oxopentanoate aldolase) thiab tom qab ntawd nkag mus rau hauv txoj kev carbon hauv nruab nrab (Daim Duab 3). Xwb, catechol raug cyclically cleaved rau cis,cis-muconate ntawm txoj kev ortho los ntawm catechol 1,2-oxygenase (C12DO). Muconate cycloisomerase, muconolactone isomerase, thiab β-ketoadipate-nollactone hydrolase hloov cis,cis-muconate mus rau 3-oxoadipate, uas nkag mus rau hauv txoj kev carbon nruab nrab ntawm succinyl-CoA thiab acetyl-CoA (Nozaki et al., 1968) (Daim Duab 3).
Hauv txoj kev gentisate (2,5-dihydroxybenzoate), lub nplhaib aromatic raug txiav los ntawm gentisate 1,2-dioxygenase (GDO) los tsim maleylpyruvate. Cov khoom no tuaj yeem hydrolyzed ncaj qha rau pyruvate thiab malate, lossis nws tuaj yeem isomerized los tsim fumarylpyruvate, uas tom qab ntawd tuaj yeem hydrolyzed rau pyruvate thiab fumarate (Larkin thiab Day, 1986). Kev xaiv ntawm lwm txoj hauv kev tau pom hauv ob qho tib si Gram-negative thiab Gram-positive kab mob ntawm cov theem biochemical thiab genetic (Morawski et al., 1997; Whyte et al., 1997). Cov kab mob Gram-negative (Pseudomonas) nyiam siv salicylic acid, uas yog tus ua rau naphthalene metabolism, decarboxylating nws mus rau catechol siv salicylate 1-hydroxylase (Gibson thiab Subramanian, 1984). Ntawm qhov tod tes, hauv cov kab mob Gram-positive (Rhodococcus), salicylate 5-hydroxylase hloov salicylic acid mus rau gentisic acid, thaum salicylic acid tsis muaj qhov cuam tshuam rau kev sau ntawv ntawm naphthalene genes (Grund et al., 1992) (Daim Duab 3).
Tau muaj kev tshaj tawm tias cov tsiaj xws li Pseudomonas CSV86, Oceanobacterium NCE312, Marinhomonas naphthotrophicus, Sphingomonas paucimobilis 2322, Vibrio cyclotrophus, Pseudomonas fluorescens LP6a, Pseudomonas thiab Mycobacterium hom tuaj yeem rhuav tshem monomethylnaphthalene lossis dimethylnaphthalene (Dean-Raymond thiab Bartha, 1975; Cane thiab Williams, 1982; Mahajan et al., 1994; Dutta et al., 1998; Hedlund et al., 1999). Ntawm lawv, txoj kev rhuav tshem 1-methylnaphthalene thiab 2-methylnaphthalene ntawm Pseudomonas sp. CSV86 tau raug kawm meej meej ntawm cov qib biochemical thiab enzymatic (Mahajan et al., 1994). 1-Methylnaphthalene yog metabolized ntawm ob txoj kev. Ua ntej, lub nplhaib aromatic yog hydroxylated (lub nplhaib tsis hloov pauv ntawm methylnaphthalene) los tsim cis-1,2-dihydroxy-1,2-dihydro-8-methylnaphthalene, uas yog oxidized ntxiv rau methyl salicylate thiab methylcatechol, thiab tom qab ntawd nkag mus rau hauv txoj kev carbon nruab nrab tom qab lub nplhaib cleavage (Daim Duab 3). Txoj kev no hu ua "txoj kev carbon qhov chaw". Hauv qhov thib ob "txoj kev detoxification", pawg methyl tuaj yeem hydroxylated los ntawm NDO los tsim 1-hydroxymethylnaphthalene, uas yog oxidized ntxiv rau 1-naphthoic acid thiab excreted rau hauv kab lis kev cai medium ua ib qho khoom tuag-kawg. Cov kev tshawb fawb tau qhia tias hom CSV86 tsis tuaj yeem loj hlob ntawm 1- thiab 2-naphthoic acid ua lub zog carbon thiab lub zog, lees paub nws txoj kev detoxification (Mahajan et al., 1994; Basu et al., 2003). Hauv 2-methylnaphthalene, pawg methyl raug hydroxylation los ntawm hydroxylase los tsim 2-hydroxymethylnaphthalene. Tsis tas li ntawd, lub nplhaib tsis hloov pauv ntawm lub nplhaib naphthalene raug hydroxylation los tsim dihydrodiol, uas tau oxidized rau 4-hydroxymethylcatechol hauv cov tshuaj enzyme-catalyzed thiab nkag mus rau hauv txoj kev carbon nruab nrab ntawm txoj kev meta-ring cleavage. Ib yam li ntawd, S. paucimobilis 2322 tau tshaj tawm tias siv NDO los hydroxylate 2-methylnaphthalene, uas tau oxidized ntxiv los tsim methyl salicylate thiab methylcatechol (Dutta et al., 1998).
Naphthoic acids (substituted/unsubstituted) yog cov khoom siv detoxification/biotransformation uas tsim thaum lub sijhawm degradation ntawm methylnaphthalene, phenanthrene thiab anthracene thiab tso tawm rau hauv cov kab lis kev cai siv. Nws tau raug tshaj tawm tias cov av cais Stenotrophomonas maltophilia CSV89 muaj peev xwm metabolize 1-naphthoic acid ua qhov chaw carbon (Phale et al., 1995). Metabolism pib nrog dihydroxylation ntawm lub nplhaib aromatic los tsim 1,2-dihydroxy-8-carboxynaphthalene. Cov diol tshwm sim yog oxidized rau catechol ntawm 2-hydroxy-3-carboxybenzylidenepyruvate, 3-formylsalicylic acid, 2-hydroxyisophthalic acid thiab salicylic acid thiab nkag mus rau hauv txoj kev carbon nruab nrab ntawm txoj kev meta-ring cleavage (Daim Duab 3).
Carbaryl yog tshuaj tua kab naphthyl carbamate. Txij li thaum muaj Kev Hloov Pauv Ntsuab hauv Is Nrias teb xyoo 1970, kev siv tshuaj chiv thiab tshuaj tua kab tau ua rau muaj kev nce ntxiv ntawm cov pa roj carbon monoxide polycyclic aromatic (PAH) los ntawm cov chaw ua liaj ua teb uas tsis yog cov ntsiab lus (Pingali, 2012; Duttagupta et al., 2020). Kwv yees li ntawm 55% (85,722,000 hectares) ntawm tag nrho cov qoob loo hauv Is Nrias teb tau kho nrog cov tshuaj tua kab. Tau tsib xyoos dhau los (2015–2020), kev ua liaj ua teb hauv Is Nrias teb tau siv qhov nruab nrab ntawm 55,000 txog 60,000 tonnes ntawm cov tshuaj tua kab txhua xyoo (Department of Cooperatives and Farmers Welfare, Ministry of Agriculture, Government of India, Lub Yim Hli 2020). Hauv thaj av Gangetic sab qaum teb thiab nruab nrab (cov xeev uas muaj cov pej xeem thiab cov pej xeem coob tshaj plaws), kev siv tshuaj tua kab rau cov qoob loo yog dav dav, nrog rau cov tshuaj tua kab feem ntau. Carbaryl (1-naphthyl-N-methylcarbamate) yog ib hom tshuaj tua kab carbamate uas muaj ntau yam tshuaj lom, siv rau hauv kev ua liaj ua teb hauv Is Nrias teb, nruab nrab ntawm 100–110 tonnes. Feem ntau muag nws lub npe lag luam Sevin thiab siv los tswj cov kab (aphids, fire ants, fleas, mites, spiders thiab ntau lwm yam kab tsuag sab nraum zoov) uas cuam tshuam rau ntau yam qoob loo (pob kws, taum pauv, paj rwb, txiv hmab txiv ntoo thiab zaub). Qee cov kab mob me me xws li Pseudomonas (NCIB 12042, 12043, C4, C5, C6, C7, Pseudomonas putida XWY-1), Rhodococcus (NCIB 12038), Sphingobacterium spp. (CF06), Burkholderia (C3), Micrococcus thiab Arthrobacter kuj siv tau los tswj lwm yam kab tsuag. Tau muaj kev tshaj tawm tias RC100 tuaj yeem rhuav tshem cov carbaryl (Larkin thiab Day, 1986; Chapalamadugu thiab Chaudhry, 1991; Hayatsu et al., 1999; Swetha thiab Phale, 2005; Trivedi et al., 2017). Txoj kev rhuav tshem cov carbaryl tau raug kawm ntau yam ntawm cov biochemical, enzymatic thiab genetic theem hauv cov av cais ntawm Pseudomonas sp. Strains C4, C5 thiab C6 (Swetha thiab Phale, 2005; Trivedi et al., 2016) (Daim duab 3). Txoj kev metabolic pib nrog hydrolysis ntawm ester bond los ntawm carbaryl hydrolase (CH3) los tsim 1-naphthol, methylamine thiab carbon dioxide. 1-naphthol ces hloov mus ua 1,2-dihydroxynaphthalene los ntawm 1-naphthol hydroxylase (1-NH4), uas yog metabolized ntxiv ntawm txoj kev carbon hauv nruab nrab ntawm salicylate thiab gentisate. Qee cov kab mob carbaryl-degrading tau tshaj tawm tias metabolize nws mus rau salicylic acid ntawm kev txiav ntawm lub nplhaib catechol ortho (Larkin thiab Day, 1986; Chapalamadugu thiab Chaudhry, 1991). Qhov tseem ceeb, cov kab mob naphthalene-degrading feem ntau metabolize salicylic acid ntawm catechol, thaum cov kab mob carbaryl-degrading nyiam metabolize salicylic acid ntawm txoj kev gentisate.
Naphthalenesulfonic acid/disulfonic acid thiab naphthylaminesulfonic acid derivatives siv tau ua cov khoom nruab nrab hauv kev tsim cov azo dyes, cov neeg sawv cev ntub dej, cov tshuaj dispersants, thiab lwm yam. Txawm hais tias cov tshuaj no muaj tshuaj lom tsawg rau tib neeg, kev ntsuam xyuas cytotoxicity tau qhia tias lawv ua rau tuag taus rau ntses, daphnia thiab algae (Greim et al., 1994). Cov neeg sawv cev ntawm genus Pseudomonas (hom A3, C22) tau tshaj tawm tias pib metabolism los ntawm ob chav hydroxylation ntawm lub nplhaib aromatic uas muaj pawg sulfonic acid los tsim dihydrodiol, uas hloov pauv mus rau 1,2-dihydroxynaphthalene los ntawm kev txiav tawm ntawm pawg sulfite (Brilon et al., 1981). Qhov tshwm sim 1,2-dihydroxynaphthalene yog catabolized ntawm txoj kev naphthalene classical, piv txwv li, txoj kev catechol lossis gentisate (Daim Duab 4). Nws tau pom tias aminonaphthalenesulfonic acid thiab hydroxynaphthalenesulfonic acid tuaj yeem raug rhuav tshem tag nrho los ntawm cov kab mob sib xyaw ua ke nrog cov txheej txheem catabolic sib xyaw (Nortemann et al., 1986). Nws tau pom tias ib tug tswv cuab ntawm pawg neeg desulfurizes aminonaphthalenesulfonic acid lossis hydroxynaphthalenesulfonic acid los ntawm 1,2-dioxygenation, thaum aminosalicylate lossis hydroxysalicylate raug tso tawm rau hauv cov kab lis kev cai ua cov metabolite tuag thiab tom qab ntawd raug coj los ntawm lwm tus tswv cuab ntawm pawg neeg. Naphthalenedisulfonic acid yog qhov tsis zoo tab sis tsis zoo biodegradable thiab yog li ntawd tuaj yeem metabolized ntawm ntau txoj hauv kev sib txawv. Thawj qhov desulfurization tshwm sim thaum lub sijhawm regioselective dihydroxylation ntawm lub nplhaib aromatic thiab pawg sulfonic acid; qhov thib ob desulfurization tshwm sim thaum lub sijhawm hydroxylation ntawm 5-sulfosalicylic acid los ntawm salicylic acid 5-hydroxylase los tsim gentisic acid, uas nkag mus rau hauv txoj kev carbon hauv nruab nrab (Brilon et al., 1981) (Daim Duab 4). Cov enzymes uas ua rau naphthalene degradation kuj yog lub luag haujlwm rau naphthalene sulfonate metabolism (Brilon et al., 1981; Keck et al., 2006).
Daim Duab 4. Txoj kev ua kom cov naphthalene sulfonate lwj. Cov lej hauv cov voj voog sawv cev rau cov enzymes uas yog lub luag haujlwm rau cov naphthyl sulfonate metabolism, zoo ib yam li cov enzymes piav qhia hauv daim duab 3.
Cov PAHs uas tsis hnyav molecular (LMW-PAHs) yog cov uas yooj yim txo, hydrophobic thiab yaj tsis zoo, thiab yog li ntawd tsis yooj yim rau kev puas tsuaj ntuj tsim. Txawm li cas los xij, cov kab mob aerobic muaj peev xwm oxidize nws los ntawm kev nqus cov pa oxygen molecular (O2). Cov enzymes no feem ntau yog cov chav kawm ntawm oxidoreductases thiab tuaj yeem ua ntau yam kev tshuaj xws li aromatic ring hydroxylation (mono- lossis dihydroxylation), dehydrogenation thiab aromatic ring cleavage. Cov khoom tau los ntawm cov kev tshuaj no nyob rau hauv lub xeev oxidation siab dua thiab yooj yim metabolized los ntawm txoj kev carbon hauv nruab nrab (Phale et al., 2020). Cov enzymes hauv txoj kev puas tsuaj tau tshaj tawm tias yog inducible. Cov haujlwm ntawm cov enzymes no yog qis heev lossis tsis tseem ceeb thaum cov hlwb loj hlob ntawm cov pa carbon yooj yim xws li glucose lossis organic acids. Rooj 3 qhia txog ntau yam enzymes (oxygenases, hydrolases, dehydrogenases, oxidases, thiab lwm yam) uas koom nrog hauv kev ua haujlwm ntawm naphthalene thiab nws cov derivatives.
Rooj 3. Cov yam ntxwv biochemical ntawm cov enzymes uas ua rau muaj kev puas tsuaj ntawm naphthalene thiab nws cov derivatives.
Cov kev tshawb fawb txog radioisotope (18O2) tau qhia tias kev koom ua ke ntawm molecular O2 rau hauv cov nplhaib aromatic los ntawm oxygenases yog qhov tseem ceeb tshaj plaws hauv kev ua kom muaj kev puas tsuaj ntxiv ntawm ib qho tshuaj (Hayaishi et al., 1955; Mason et al., 1955). Kev koom ua ke ntawm ib qho oxygen atom (O) los ntawm molecular oxygen (O2) rau hauv lub substrate yog pib los ntawm endogenous lossis exogenous monooxygenases (tseem hu ua hydroxylases). Lwm lub oxygen atom raug txo kom dej. Exogenous monooxygenases txo flavin nrog NADH lossis NADPH, thaum nyob rau hauv endomonooxygenases flavin raug txo los ntawm lub substrate. Qhov chaw ntawm hydroxylation ua rau muaj kev sib txawv hauv kev tsim khoom. Piv txwv li, salicylate 1-hydroxylase hydroxylates salicylic acid ntawm C1 txoj haujlwm, tsim catechol. Ntawm qhov tod tes, cov tshuaj salicylate 5-hydroxylase ntau yam (muaj reductase, ferredoxin, thiab oxygenase subunits) hydroxylates salicylic acid ntawm C5 txoj haujlwm, tsim cov gentisic acid (Yamamoto et al., 1965).
Dioxygenases muab ob lub O2 atoms tso rau hauv lub substrate. Nyob ntawm cov khoom tsim, lawv raug muab faib ua lub nplhaib hydroxylating dioxygenases thiab lub nplhaib cleaving dioxygenases. Lub nplhaib hydroxylating dioxygenases hloov cov aromatic substrates rau hauv cis-dihydrodiols (piv txwv li, naphthalene) thiab dav dav ntawm cov kab mob. Txog niaj hnub no, nws tau pom tias cov kab mob uas muaj lub nplhaib hydroxylating dioxygenases muaj peev xwm loj hlob ntawm ntau yam aromatic carbon qhov chaw, thiab cov enzymes no tau muab faib ua NDO (naphthalene), toluene dioxygenase (TDO, toluene), thiab biphenyl dioxygenase (BPDO, biphenyl). Ob leeg NDO thiab BPDO tuaj yeem ua rau muaj kev sib txuas ob zaug thiab kev sib txuas ntawm cov saw hlau ntawm ntau yam polycyclic aromatic hydrocarbons (toluene, nitrotoluene, xylene, ethylbenzene, naphthalene, biphenyl, fluorene, indole, methylnaphthalene, naphthalenesulfonate, phenanthrene, anthracene, acetophenone, thiab lwm yam) (Boyd thiab Sheldrake, 1998; Phale et al., 2020). NDO yog ib lub cev muaj ntau yam uas muaj oxidoreductase, ferredoxin, thiab ib qho chaw ua haujlwm uas muaj oxygenase (Gibson thiab Subramanian, 1984; Resnick et al., 1996). Lub chaw catalytic ntawm NDO muaj ib qho loj α subunit thiab ib qho me me β subunit teeb tsa hauv α3β3 configuration. NDO yog ib tsev neeg loj ntawm cov pa oxygenases thiab nws cov α-subunit muaj ib qho chaw Rieske [2Fe-2S] thiab ib qho mononuclear non-heme hlau, uas txiav txim siab qhov tshwj xeeb ntawm NDO (Parales et al., 1998). Feem ntau, hauv ib lub voj voog catalytic, ob lub electrons los ntawm kev txo qis ntawm pyridine nucleotide raug xa mus rau Fe (II) ion hauv qhov chaw nquag ntawm reductase, ferredoxin thiab Rieske qhov chaw. Cov khoom sib npaug txo qis ua rau cov pa oxygen molecular, uas yog qhov yuav tsum tau ua rau substrate dihydroxylation (Ferraro et al., 2005). Txog niaj hnub no, tsuas yog ob peb NDOs tau raug ntxuav thiab piav qhia meej los ntawm ntau hom kab mob sib txawv thiab kev tswj hwm caj ces ntawm txoj hauv kev koom nrog hauv kev puas tsuaj naphthalene tau kawm meej (Resnick et al., 1996; Parales et al., 1998; Karlsson et al., 2003). Cov enzymes uas ua rau lub nplhaib tawg (endo- lossis ortho-ring-cleaving enzymes thiab exodiol- lossis meta-ring-cleaving enzymes) ua haujlwm rau cov tshuaj hydroxylated aromatic. Piv txwv li, ortho-ring-cleaving dioxygenase yog catechol-1,2-dioxygenase, thaum meta-ring-cleaving dioxygenase yog catechol-2,3-dioxygenase (Kojima et al., 1961; Nozaki et al., 1968). Ntxiv rau ntau yam oxygenases, kuj tseem muaj ntau yam dehydrogenases uas ua rau lub dehydrogenation ntawm aromatic dihydrodiols, alcohols thiab aldehydes thiab siv NAD+/NADP+ ua electron acceptors, uas yog qee cov enzymes tseem ceeb uas koom nrog hauv kev ua metabolism (Gibson thiab Subramanian, 1984; Shaw thiab Harayama, 1990; Fahle et al., 2020).
Cov enzymes xws li hydrolases (esterases, amidases) yog ib chav kawm tseem ceeb thib ob ntawm cov enzymes uas siv dej los txiav covalent bonds thiab qhia txog qhov dav dav substrate specificity. Carbaryl hydrolase thiab lwm yam hydrolases raug suav hais tias yog cov khoom ntawm periplasm (transmembrane) hauv cov tswv cuab ntawm Gram-negative bacteria (Kamini et al., 2018). Carbaryl muaj ob qho tib si amide thiab ester linkage; yog li ntawd, nws tuaj yeem hydrolyzed los ntawm esterase lossis amidase los tsim 1-naphthol. Carbaryl hauv Rhizobium rhizobium strain AC10023 thiab Arthrobacter strain RC100 tau tshaj tawm tias ua haujlwm ua esterase thiab amidase, raws li. Carbaryl hauv Arthrobacter strain RC100 kuj ua haujlwm ua amidase. RC100 tau pom tias hydrolyze plaub hom tshuaj tua kab N-methylcarbamate xws li carbaryl, methomyl, mefenamic acid thiab XMC (Hayaatsu et al., 2001). Tau tshaj tawm tias CH hauv Pseudomonas sp. C5pp tuaj yeem ua haujlwm rau carbaryl (100% kev ua haujlwm) thiab 1-naphthyl acetate (36% kev ua haujlwm), tab sis tsis yog rau 1-naphthylacetamide, qhia tias nws yog esterase (Trivedi et al., 2016).
Cov kev tshawb fawb txog biochemical, cov qauv kev tswj hwm enzyme, thiab kev tshuaj xyuas genetic tau qhia tias cov noob naphthalene degradation muaj ob lub inducible regulatory units lossis "operons": nah ("upstream pathway", hloov naphthalene mus rau salicylic acid) thiab sal ("downstream pathway", hloov salicylic acid mus rau hauv central carbon pathway ntawm catechol). Salicylic acid thiab nws cov analogues tuaj yeem ua haujlwm ua inducers (Shamsuzzaman thiab Barnsley, 1974). Thaum muaj glucose lossis organic acids, operon raug repressed. Daim duab 5 qhia txog tag nrho cov genetic organization ntawm naphthalene degradation (hauv operon daim ntawv). Ntau lub npe variants/forms ntawm nah gene (ndo/pah/dox) tau piav qhia thiab pom tias muaj cov sequence homology siab (90%) ntawm txhua hom Pseudomonas (Abbasian et al., 2016). Cov noob ntawm naphthalene upstream pathway feem ntau tau teeb tsa hauv kev sib koom siab raws li pom hauv Daim duab 5A. Muaj ib tug gene ntxiv, nahQ, uas koom nrog rau hauv kev ua haujlwm ntawm naphthalene thiab feem ntau nyob nruab nrab ntawm nahC thiab nahE, tab sis nws txoj haujlwm tiag tiag tseem tsis tau piav qhia meej. Ib yam li ntawd, tus gene nahY, uas yog lub luag haujlwm rau naphthalene-sensitive chemotaxis, tau pom nyob rau ntawm qhov kawg ntawm nah operon hauv qee tus tswv cuab. Hauv Ralstonia sp., tus gene U2 uas encoding glutathione S-transferase (gsh) tau pom tias nyob nruab nrab ntawm nahAa thiab nahAb tab sis tsis cuam tshuam rau cov yam ntxwv ntawm kev siv naphthalene (Zylstra et al., 1997).
Daim Duab 5. Kev teeb tsa caj ces thiab kev sib txawv ntawm cov noob caj noob ces uas pom thaum lub sijhawm naphthalene lwj ntawm cov kab mob bacterial; (A) Txoj kev naphthalene sab saud, kev hloov pauv ntawm naphthalene mus rau salicylic acid; (B) Txoj kev naphthalene qis dua, salicylic acid ntawm catechol mus rau txoj kev carbon nruab nrab; (C) salicylic acid ntawm gentisate mus rau txoj kev carbon nruab nrab.
Txoj kev "qis dua" (sal operon) feem ntau muaj nahGTHINLMOKJ thiab hloov salicylate mus rau pyruvate thiab acetaldehyde ntawm txoj kev catechol metaring cleavage. Lub noob nahG (encoding salicylate hydroxylase) tau pom tias khaws cia rau ntawm qhov kawg ntawm lub operon (Daim duab 5B). Piv nrog rau lwm cov kab mob naphthalene-degrading, hauv P. putida CSV86 lub nah thiab sal operons yog tandem thiab muaj feem cuam tshuam ze heev (kwv yees li 7.5 kb). Hauv qee cov kab mob Gram-negative, xws li Ralstonia sp. U2, Polaromonas naphthalenivorans CJ2, thiab P. putida AK5, naphthalene yog metabolized ua lub hauv paus carbon metabolite ntawm txoj kev gentisate (hauv daim ntawv ntawm sgp/nag operon). Feem ntau cov gene cassette yog sawv cev rau hauv daim ntawv nagAaGHAbAcAdBFCQEDJI, qhov twg nagR (encoding ib tug LysR-type regulator) nyob rau sab saud kawg (Daim Duab 5C).
Carbaryl nkag mus rau hauv lub voj voog carbon hauv nruab nrab ntawm kev ua haujlwm ntawm 1-naphthol, 1,2-dihydroxynaphthalene, salicylic acid, thiab gentisic acid (Daim Duab 3). Raws li kev tshawb fawb txog caj ces thiab kev ua haujlwm ntawm lub cev, nws tau raug pom zoo kom faib txoj hauv kev no mus rau hauv "upstream" (kev hloov pauv ntawm carbaryl mus rau salicylic acid), "nruab nrab" (kev hloov pauv ntawm salicylic acid mus rau gentisic acid), thiab "downstream" (kev hloov pauv ntawm gentisic acid mus rau txoj hauv kev carbon hauv nruab nrab) (Singh et al., 2013). Kev tshuaj xyuas genomic ntawm C5pp (supercontig A, 76.3 kb) tau qhia tias mcbACBDEF gene koom nrog kev hloov pauv ntawm carbaryl mus rau salicylic acid, ua raws li mcbIJKL hauv kev hloov pauv ntawm salicylic acid mus rau gentisic acid, thiab mcbOQP hauv kev hloov pauv ntawm gentisic acid mus rau cov pa roj carbon nruab nrab (fumarate thiab pyruvate, Trivedi et al., 2016) (Daim Duab 6).
Tau muaj kev tshaj tawm tias cov enzymes uas koom nrog kev rhuav tshem cov aromatic hydrocarbons (xws li naphthalene thiab salicylic acid) tuaj yeem raug tsim los ntawm cov tshuaj sib xws thiab raug txwv los ntawm cov pa roj carbon yooj yim xws li glucose lossis organic acids (Shingler, 2003; Phale et al., 2019, 2020). Ntawm ntau txoj kev metabolic ntawm naphthalene thiab nws cov derivatives, cov yam ntxwv tswj hwm ntawm naphthalene thiab carbaryl tau raug kawm txog qee qhov. Rau naphthalene, cov noob caj noob ces hauv ob txoj kev upstream thiab downstream yog tswj hwm los ntawm NahR, tus LysR-hom trans-acting zoo regulator. Nws yog qhov yuav tsum tau rau kev induction ntawm nah gene los ntawm salicylic acid thiab nws cov kev qhia siab tom qab (Yen thiab Gunsalus, 1982). Ntxiv mus, kev tshawb fawb tau qhia tias integrative host factor (IHF) thiab XylR (sigma 54-dependent transcriptional regulator) kuj tseem ceeb rau kev ua haujlwm transcriptional ntawm cov noob caj noob ces hauv naphthalene metabolism (Ramos et al., 1997). Cov kev tshawb fawb tau qhia tias cov enzymes ntawm txoj kev qhib catechol meta-ring, uas yog catechol 2,3-dioxygenase, raug tsim tawm thaum muaj naphthalene thiab/lossis salicylic acid (Basu et al., 2006). Cov kev tshawb fawb tau qhia tias cov enzymes ntawm txoj kev qhib catechol ortho-ring, uas yog catechol 1,2-dioxygenase, raug tsim tawm thaum muaj benzoic acid thiab cis,cis-muconate (Parsek et al., 1994; Tover et al., 2001).
Hauv hom kab mob C5pp, tsib lub noob caj noob ces, mcbG, mcbH, mcbN, mcbR thiab mcbS, encode cov regulators uas yog tsev neeg LysR/TetR ntawm cov transcriptional regulators uas muaj lub luag haujlwm tswj kev puas tsuaj ntawm carbaryl. Lub noob caj noob ces mcbG tau pom tias muaj feem cuam tshuam nrog LysR-type regulator PhnS (58% amino acid identity) uas koom nrog hauv phenanthrene metabolism hauv Burkholderia RP00725 (Trivedi et al., 2016). Lub noob caj noob ces mcbH tau pom tias koom nrog hauv txoj kev nruab nrab (hloov pauv ntawm salicylic acid mus rau gentisic acid) thiab yog LysR-type transcriptional regulator NagR/DntR/NahR hauv Pseudomonas thiab Burkholderia. Cov tswv cuab ntawm tsev neeg no tau tshaj tawm tias lees paub salicylic acid ua ib qho molecule effector tshwj xeeb rau kev ua kom cov noob caj noob ces puas tsuaj. Ntawm qhov tod tes, peb lub noob caj noob ces, mcbN, mcbR thiab mcbS, uas yog LysR thiab TetR hom transcriptional regulators, tau txheeb xyuas hauv txoj kev nqes mus (gentisate-central carbon pathway metabolites).
Hauv cov prokaryotes, cov txheej txheem hloov pauv noob caj noob ces (kev tau txais, kev sib pauv, lossis kev hloov pauv) ntawm plasmids, transposons, prophages, genomic islands, thiab integrative conjugative elements (ICE) yog cov ua rau muaj kev hloov pauv hauv cov genomes ntawm cov kab mob, ua rau muaj kev nce lossis poob ntawm cov haujlwm / cwj pwm tshwj xeeb. Nws tso cai rau cov kab mob kom hloov kho sai rau ntau yam xwm txheej ib puag ncig, muab cov txiaj ntsig zoo rau kev hloov pauv metabolism rau tus tswv tsev, xws li kev puas tsuaj ntawm cov tshuaj aromatic. Kev hloov pauv metabolic feem ntau ua tiav los ntawm kev kho kom zoo ntawm cov operons degradation, lawv cov txheej txheem tswj hwm, thiab cov enzyme tshwj xeeb, uas ua rau muaj kev puas tsuaj ntawm ntau yam tshuaj aromatic (Nojiri et al., 2004; Phale et al., 2019, 2020). Cov gene cassettes rau naphthalene degradation tau pom tias nyob ntawm ntau yam khoom siv xws li plasmids (conjugative thiab non-conjugative), transposons, genomes, ICEs, thiab kev sib xyaw ntawm ntau hom kab mob sib txawv (Daim Duab 5). Hauv Pseudomonas G7, cov nah thiab sal operons ntawm plasmid NAH7 raug sau ua tib qho kev taw qhia thiab yog ib feem ntawm qhov tsis zoo transposon uas xav tau transposase Tn4653 rau kev txav mus los (Sota et al., 2006). Hauv Pseudomonas hom NCIB9816-4, cov gene tau pom ntawm conjugative plasmid pDTG1 ua ob lub operons (kwv yees li 15 kb sib nrug) uas tau sau ua ob qho kev taw qhia (Dennis thiab Zylstra, 2004). Hauv Pseudomonas putida hom AK5, cov plasmid tsis-conjugative pAK5 encodes cov enzyme uas ua rau naphthalene degradation ntawm txoj kev gentisate (Izmalkova et al., 2013). Hauv Pseudomonas hom PMD-1, nah operon nyob rau ntawm lub chromosome, thaum lub sal operon nyob rau ntawm lub conjugative plasmid pMWD-1 (Zuniga et al., 1981). Txawm li cas los xij, hauv Pseudomonas stutzeri AN10, txhua lub noob naphthalene degradation (nah thiab sal operons) nyob rau ntawm lub chromosome thiab tej zaum yuav raug nrhiav los ntawm kev hloov pauv, kev sib sau ua ke, thiab kev hloov pauv tshiab (Bosch et al., 2000). Hauv Pseudomonas sp. CSV86, nah thiab sal operons nyob rau hauv lub genome hauv daim ntawv ntawm ICE (ICECSV86). Cov qauv no yog tiv thaiv los ntawm tRNAGly ua raws li kev rov ua dua ncaj qha qhia txog qhov chaw sib xyaw ua ke / txuas (attR thiab attL) thiab phage-zoo li integrase nyob ntawm ob qho kawg ntawm tRNAGly, yog li cov qauv zoo ib yam li ICEclc element (ICEclcB13 hauv Pseudomonas knackmusii rau chlorocatechol degradation). Nws tau tshaj tawm tias cov noob caj noob ces ntawm ICE tuaj yeem hloov pauv los ntawm kev sib txuas nrog qhov zaus hloov pauv qis heev (10-8), yog li hloov cov khoom degradation rau tus neeg tau txais (Basu thiab Phale, 2008; Phale et al., 2019).
Feem ntau ntawm cov noob caj noob ces uas ua rau carbaryl puas tsuaj nyob rau ntawm plasmids. Arthrobacter sp. RC100 muaj peb plasmids (pRC1, pRC2 thiab pRC300) uas ob lub plasmids sib txuas, pRC1 thiab pRC2, encode cov enzymes uas hloov carbaryl mus rau gentisate. Ntawm qhov tod tes, cov enzymes koom nrog kev hloov pauv ntawm gentisate mus rau cov pa roj carbon metabolites hauv nruab nrab nyob rau ntawm chromosome (Hayaatsu et al., 1999). Cov kab mob ntawm genus Rhizobium. Hom AC100, siv rau kev hloov pauv ntawm carbaryl mus rau 1-naphthol, muaj plasmid pAC200, uas nqa cov cehA gene encoding CH ua ib feem ntawm Tnceh transposon uas nyob ib puag ncig los ntawm cov kab ke zoo li cov khoom siv (istA thiab istB) (Hashimoto et al., 2002). Hauv Sphingomonas hom CF06, cov noob carbaryl degradation ntseeg tau tias muaj nyob rau hauv tsib plasmids: pCF01, pCF02, pCF03, pCF04, thiab pCF05. Cov DNA homology ntawm cov plasmids no yog siab, qhia txog qhov muaj nyob ntawm qhov xwm txheej rov ua dua ntawm cov noob (Feng et al., 1997). Hauv cov carbaryl-degrading symbiont uas muaj ob hom Pseudomonas, hom 50581 muaj cov plasmid conjugative pCD1 (50 kb) encoding mcd carbaryl hydrolase gene, thaum cov plasmid conjugative hauv hom 50552 encodes 1-naphthol-degrading enzyme (Chapalamadugu thiab Chaudhry, 1991). Hauv Achromobacter hom WM111, cov noob mcd furadan hydrolase nyob ntawm 100 kb plasmid (pPDL11). Cov noob caj noob ces no tau pom tias muaj nyob rau ntawm ntau hom plasmids (100, 105, 115 lossis 124 kb) hauv cov kab mob sib txawv los ntawm thaj chaw sib txawv (Parekh et al., 1995). Hauv Pseudomonas sp. C5pp, txhua hom noob caj noob ces uas ua rau carbaryl degradation nyob hauv ib hom genome uas muaj 76.3 kb ntawm cov kab ke (Trivedi et al., 2016). Kev tshuaj xyuas genome (6.15 Mb) tau qhia txog qhov muaj 42 MGEs thiab 36 GEIs, uas 17 MGEs nyob hauv supercontig A (76.3 kb) nrog rau qhov nruab nrab asymmetric G+C cov ntsiab lus (54–60 mol%), qhia txog tej yam uas yuav muaj tau cov xwm txheej hloov pauv noob caj noob ces (Trivedi et al., 2016). P. putida XWY-1 qhia txog kev npaj zoo sib xws ntawm cov noob caj noob ces carbaryl-degrading, tab sis cov noob caj noob ces no nyob rau ntawm ib hom plasmid (Zhu et al., 2019).
Ntxiv rau qhov ua tau zoo ntawm kev zom zaub mov ntawm cov qib biochemical thiab genomic, cov kab mob me me kuj tseem ua rau pom lwm yam khoom lossis cov lus teb xws li chemotaxis, cov khoom hloov kho ntawm qhov chaw ntawm lub cell, kev faib ua pawg, kev siv tshwj xeeb, kev tsim cov biosurfactant, thiab lwm yam, uas pab lawv zom cov pa phem aromatic hauv cov chaw muaj kuab paug (Daim Duab 7).
Daim Duab 7. Cov tswv yim teb sib txawv ntawm cov cellular ntawm cov kab mob uas ua rau cov hydrocarbon aromatic zoo tagnrho rau kev ua kom cov tshuaj lom neeg txawv teb chaws puas tsuaj tau zoo.
Cov lus teb chemotactic raug suav hais tias yog cov yam tseem ceeb uas ua rau muaj kev puas tsuaj ntawm cov organic pollutants hauv cov ecosystem heterogeneously polluted. (2002) tau qhia tias chemotaxis ntawm Pseudomonas sp. G7 rau naphthalene ua rau muaj kev puas tsuaj ntawm naphthalene hauv cov kab ke hauv dej. Cov kab mob qus G7 ua rau naphthalene puas tsuaj sai dua li cov kab mob mutant uas tsis muaj chemotaxis. Cov protein NahY (538 amino acids nrog membrane topology) tau pom tias tau sau ua ke nrog cov noob metacleavage pathway ntawm NAH7 plasmid, thiab zoo li chemotaxis transducers, cov protein no zoo li ua haujlwm ua chemoreceptor rau naphthalene degradation (Grimm thiab Harwood 1997). Lwm txoj kev tshawb fawb los ntawm Hansel et al. (2009) tau qhia tias cov protein yog chemotactic, tab sis nws qhov kev puas tsuaj siab. (2011) tau ua pov thawj txog kev teb chemotactic ntawm Pseudomonas (P. putida) rau cov pa roj naphthalene, qhov twg cov pa roj diffusion ua rau muaj kev ntws ntawm naphthalene mus rau cov cell, uas tswj cov kev teb chemotactic ntawm cov cell. Cov kws tshawb fawb tau siv qhov kev coj cwj pwm chemotactic no los tsim cov microbes uas yuav ua rau kom muaj kev puas tsuaj ntau dua. Kev tshawb fawb tau qhia tias cov kev kho mob chemosensory kuj tswj hwm lwm yam haujlwm ntawm cellular xws li kev faib cell, kev tswj hwm lub voj voog cell, thiab kev tsim biofilm, yog li pab tswj hwm qhov kev puas tsuaj ntau dua. Txawm li cas los xij, kev siv cov khoom no (chemotaxis) rau kev puas tsuaj zoo raug cuam tshuam los ntawm ntau qhov kev txwv. Cov teeb meem loj yog: (a) cov paralogous receptors sib txawv lees paub cov tshuaj sib xyaw / ligands tib yam; (b) muaj cov receptors lwm txoj hauv kev, piv txwv li, lub zog tropism; (c) qhov sib txawv tseem ceeb hauv cov cheeb tsam sensory ntawm tib tsev neeg receptor; thiab (d) tsis muaj cov ntaub ntawv ntawm cov protein sensor tseem ceeb ntawm cov kab mob (Ortega et al., 2017; Martin-Mora et al., 2018). Qee zaum, qhov kev puas tsuaj ntawm cov aromatic hydrocarbons tsim ntau yam metabolites / intermediates, uas tej zaum yuav yog chemotactic rau ib pawg ntawm cov kab mob tab sis repulsive rau lwm tus, ntxiv rau qhov nyuaj rau cov txheej txheem. Txhawm rau txheeb xyuas cov kev sib cuam tshuam ntawm ligands (aromatic hydrocarbons) nrog cov tshuaj receptors, peb tau tsim cov hybrid sensor proteins (PcaY, McfR, thiab NahY) los ntawm kev sib xyaw cov sensor thiab signaling domains ntawm Pseudomonas putida thiab Escherichia coli, uas tsom mus rau cov receptors rau aromatic acids, TCA intermediates, thiab naphthalene, feem (Luu et al., 2019).
Nyob rau hauv kev cuam tshuam ntawm naphthalene thiab lwm yam polycyclic aromatic hydrocarbons (PAHs), cov qauv ntawm cov kab mob daim nyias nyias thiab kev ncaj ncees ntawm cov kab mob me me hloov pauv ntau heev. Cov kev tshawb fawb tau qhia tias naphthalene cuam tshuam rau kev sib cuam tshuam ntawm cov saw hlau acyl los ntawm kev sib cuam tshuam hydrophobic, yog li ua rau qhov o thiab fluidity ntawm daim nyias nyias (Sikkema et al., 1995). Txhawm rau tiv thaiv qhov cuam tshuam tsis zoo no, cov kab mob tswj cov kua membrane los ntawm kev hloov pauv qhov piv thiab cov rog acid sib xyaw ntawm iso / anteiso branched-chain fatty acids thiab isomerizing cis-unsaturated fatty acids mus rau hauv cov trans-isomers sib xws (Heipieper thiab de Bont, 1994). Hauv Pseudomonas stutzeri loj hlob ntawm kev kho naphthalene, qhov sib piv ntawm cov rog saturated rau unsaturated nce ntxiv los ntawm 1.1 mus rau 2.1, thaum nyob rau hauv Pseudomonas JS150 qhov sib piv no nce ntxiv los ntawm 7.5 mus rau 12.0 (Mrozik et al., 2004). Thaum loj hlob ntawm naphthalene, Achromobacter KAs 3–5 hlwb tau pom tias muaj kev sib sau ua ke ntawm cov hlwb nyob ib puag ncig cov siv lead ua naphthalene thiab txo qis ntawm cov nqi ntawm cov hlwb saum npoo (los ntawm -22.5 txog -2.5 mV) nrog rau cytoplasmic condensation thiab vacuolization, qhia txog kev hloov pauv hauv cov qauv ntawm cov hlwb thiab cov khoom ntawm cov hlwb saum npoo (Mohapatra et al., 2019). Txawm hais tias kev hloov pauv ntawm cov hlwb/nto ntawm qhov chaw yog cuam tshuam ncaj qha nrog kev nqus zoo dua ntawm cov pa phem aromatic, cov tswv yim bioengineering tseem ceeb tsis tau raug kho kom zoo. Kev tswj hwm ntawm cov duab ntawm cov hlwb tsis tshua muaj siv los ua kom zoo dua cov txheej txheem biological (Volke thiab Nikel, 2018). Kev rho tawm cov noob caj noob ces cuam tshuam rau kev faib cov hlwb ua rau muaj kev hloov pauv hauv cov qauv ntawm cov hlwb. Kev rho tawm cov noob caj noob ces cuam tshuam rau kev faib cov hlwb ua rau muaj kev hloov pauv hauv cov qauv ntawm cov hlwb. Hauv Bacillus subtilis, cov protein ntawm cov hlwb septum SepF tau pom tias koom nrog hauv kev tsim cov hlwb thiab yog qhov xav tau rau cov kauj ruam tom ntej ntawm kev faib cov hlwb, tab sis nws tsis yog cov noob caj noob ces tseem ceeb. Kev rho tawm cov noob caj noob ces uas encoding peptide glycan hydrolases hauv Bacillus subtilis ua rau cov cell ntev zuj zus, nce qhov kev loj hlob tshwj xeeb, thiab txhim kho lub peev xwm tsim cov enzyme (Cui et al., 2018).
Kev faib ua feem ntawm txoj kev puas tsuaj ntawm carbaryl tau raug pom zoo kom ua tiav kev puas tsuaj zoo ntawm Pseudomonas hom C5pp thiab C7 (Kamini et al., 2018). Nws tau pom zoo tias carbaryl raug thauj mus rau hauv qhov chaw periplasmic los ntawm sab nraud membrane septum thiab / lossis los ntawm diffusible porins. CH yog ib qho periplasmic enzyme uas catalyzes lub hydrolysis ntawm carbaryl rau 1-naphthol, uas ruaj khov dua, hydrophobic ntau dua thiab lom ntau dua. CH yog localized nyob rau hauv periplasm thiab muaj qhov tsis tshua muaj affinity rau carbaryl, yog li tswj kev tsim ntawm 1-naphthol, yog li tiv thaiv nws cov khoom sib sau ua ke hauv cov hlwb thiab txo nws cov tshuaj lom rau cov hlwb (Kamini et al., 2018). Qhov tshwm sim 1-naphthol raug thauj mus rau hauv cytoplasm hla lub membrane sab hauv los ntawm kev faib thiab / lossis diffusion, thiab tom qab ntawd hydroxylated rau 1,2-dihydroxynaphthalene los ntawm high-affinity enzyme 1NH rau kev ua kom cov metabolism ntxiv hauv txoj kev carbon hauv nruab nrab.
Txawm hais tias cov kab mob me me muaj peev xwm ua rau cov pa roj carbon xenobiotic puas tsuaj, cov qauv hierarchical ntawm lawv siv (piv txwv li, kev siv cov pa roj carbon yooj yim dua li cov pa roj carbon nyuaj) yog qhov teeb meem loj rau kev puas tsuaj ntawm biodegradation. Qhov muaj thiab kev siv cov pa roj carbon yooj yim txo qis cov noob encoding enzymes uas rhuav tshem cov pa roj carbon nyuaj / tsis nyiam xws li PAHs. Ib qho piv txwv zoo uas tau kawm yog tias thaum glucose thiab lactose raug pub rau Escherichia coli, glucose siv tau zoo dua li lactose (Jacob thiab Monod, 1965). Pseudomonas tau tshaj tawm tias rhuav tshem ntau yam PAHs thiab xenobiotic compounds ua cov pa roj carbon. Cov hierarchy ntawm kev siv cov pa roj carbon hauv Pseudomonas yog cov organic acids> glucose> aromatic compounds (Hylemon thiab Phibbs, 1972; Collier et al., 1996). Txawm li cas los xij, muaj ib qho kev zam. Nthuav, Pseudomonas sp. CSV86 qhia txog cov qauv hierarchical tshwj xeeb uas siv cov aromatic hydrocarbons (benzoic acid, naphthalene, thiab lwm yam) es tsis yog glucose thiab co-metabolizes aromatic hydrocarbons nrog cov organic acids (Basu et al., 2006). Hauv cov kab mob no, cov noob rau kev puas tsuaj thiab kev thauj mus los ntawm aromatic hydrocarbons tsis raug txo qis txawm tias muaj qhov chaw thib ob ntawm cov pa roj carbon xws li glucose lossis organic acids. Thaum loj hlob hauv glucose thiab aromatic hydrocarbons nruab nrab, nws tau pom tias cov noob rau kev thauj mus los ntawm glucose thiab metabolism tau raug txo qis, aromatic hydrocarbons tau siv hauv thawj theem cav, thiab glucose tau siv hauv theem log thib ob (Basu et al., 2006; Choudhary et al., 2017). Ntawm qhov tod tes, qhov muaj cov organic acids tsis cuam tshuam rau kev qhia tawm ntawm aromatic hydrocarbon metabolism, yog li cov kab mob no xav tias yuav yog ib hom kab mob rau kev tshawb fawb biodegradation (Phale et al., 2020).
Nws paub zoo tias kev hloov pauv hydrocarbon tuaj yeem ua rau muaj kev ntxhov siab oxidative thiab kev nce ntxiv ntawm cov enzymes antioxidant hauv cov kab mob me me. Kev puas tsuaj ntawm naphthalene tsis zoo hauv cov hlwb theem ruaj khov thiab nyob rau hauv qhov muaj cov tshuaj lom ua rau muaj cov tshuaj reactive oxygen (ROS) (Kang et al. 2006). Txij li thaum naphthalene-degrading enzymes muaj cov pawg hlau-sulfur, nyob rau hauv kev ntxhov siab oxidative, cov hlau hauv heme thiab hlau-sulfur proteins yuav raug oxidized, ua rau cov protein tsis ua haujlwm. Ferredoxin-NADP + reductase (Fpr), ua ke nrog superoxide dismutase (SOD), mediates qhov kev cuam tshuam redox rov qab ntawm NADP + / NADPH thiab ob lub molecules ntawm ferredoxin lossis flavodoxin, yog li scavenging ROS thiab rov qab kho qhov chaw hlau-sulfur nyob rau hauv kev ntxhov siab oxidative (Li et al. 2006). Tau muaj kev tshaj tawm tias ob qho tib si Fpr thiab SodA (SOD) hauv Pseudomonas tuaj yeem raug tsim los ntawm kev ntxhov siab oxidative, thiab kev nce ntxiv ntawm SOD thiab catalase cov haujlwm tau pom hauv plaub hom Pseudomonas (O1, W1, As1, thiab G1) thaum lub sijhawm loj hlob hauv qab naphthalene-ntxiv cov xwm txheej (Kang et al., 2006). Cov kev tshawb fawb tau qhia tias kev ntxiv cov antioxidants xws li ascorbic acid lossis ferrous iron (Fe2+) tuaj yeem ua rau kom muaj kev loj hlob ntawm naphthalene. Thaum Rhodococcus erythropolis loj hlob hauv naphthalene medium, kev sau cov noob caj noob ces cytochrome P450 uas cuam tshuam nrog kev ntxhov siab oxidative suav nrog sodA (Fe/Mn superoxide dismutase), sodC (Cu/Zn superoxide dismutase), thiab recA tau nce ntxiv (Sazykin et al., 2019). Kev tshuaj xyuas cov protein sib piv ntawm cov hlwb Pseudomonas uas cog rau hauv naphthalene qhia tau hais tias kev nce ntxiv ntawm ntau yam protein uas cuam tshuam nrog kev teb rau kev ntxhov siab oxidative yog ib txoj hauv kev daws teeb meem kev ntxhov siab (Herbst et al., 2013).
Cov kab mob me me tau tshaj tawm tias tsim cov biosurfactants nyob rau hauv qhov kev ua ntawm cov pa roj carbon hydrophobic. Cov surfactants no yog cov amphiphilic surfactants uas tuaj yeem tsim cov aggregates ntawm cov roj-dej lossis cua-dej interfaces. Qhov no txhawb nqa pseudo-solubilization thiab pab txhawb kev adsorption ntawm aromatic hydrocarbons, ua rau muaj kev puas tsuaj biodegradation zoo (Rahman et al., 2002). Vim yog cov khoom no, biosurfactants tau siv dav hauv ntau yam lag luam. Kev ntxiv cov tshuaj surfactants lossis biosurfactants rau cov kab mob bacterial tuaj yeem txhim kho kev ua haujlwm thiab tus nqi ntawm hydrocarbon degradation. Ntawm cov biosurfactants, rhamnolipids tsim los ntawm Pseudomonas aeruginosa tau raug kawm dav thiab piav qhia (Hisatsuka et al., 1971; Rahman et al., 2002). Tsis tas li ntawd xwb, lwm hom biosurfactants suav nrog lipopeptides (mucins los ntawm Pseudomonas fluorescens), emulsifier 378 (los ntawm Pseudomonas fluorescens) (Rosenberg thiab Ron, 1999), trehalose disaccharide lipids los ntawm Rhodococcus (Ramdahl, 1985), lichenin los ntawm Bacillus (Saraswathy thiab Hallberg, 2002), thiab surfactant los ntawm Bacillus subtilis (Siegmund thiab Wagner, 1991) thiab Bacillus amyloliquefaciens (Zhi et al., 2017). Cov surfactants muaj zog no tau pom tias txo qhov nro ntawm qhov chaw los ntawm 72 dynes/cm mus rau tsawg dua 30 dynes/cm, uas ua rau kev nqus hydrocarbon zoo dua. Tau muaj kev tshaj tawm tias Pseudomonas, Bacillus, Rhodococcus, Burkholderia thiab lwm hom kab mob tuaj yeem tsim ntau yam rhamnolipid thiab glycolipid-based biosurfactants thaum cog rau hauv naphthalene thiab methylnaphthalene media (Kanga et al., 1997; Puntus et al., 2005). Pseudomonas maltophilia CSV89 tuaj yeem tsim cov extracellular biosurfactant Biosur-Pm thaum cog rau ntawm cov aromatic compounds xws li naphthoic acid (Phale et al., 1995). Lub kinetics ntawm Biosur-Pm tsim tau qhia tias nws cov synthesis yog ib qho kev loj hlob- thiab pH-dependent txheej txheem. Nws tau pom tias qhov ntau ntawm Biosur-Pm tsim los ntawm cov cell ntawm pH nruab nrab yog siab dua li ntawm pH 8.5. Cov cell loj hlob ntawm pH 8.5 yog hydrophobic ntau dua thiab muaj affinity siab dua rau aromatic thiab aliphatic compounds dua li cov cell loj hlob ntawm pH 7.0. Hauv Rhodococcus spp. N6, qhov sib piv ntawm cov pa roj carbon rau nitrogen (C:N) ntau dua thiab kev txwv hlau yog cov xwm txheej zoo tshaj plaws rau kev tsim cov biosurfactants sab nraud (Mutalik et al., 2008). Tau muaj kev sim ua kom zoo dua qhov biosynthesis ntawm biosurfactants (surfactins) los ntawm kev ua kom zoo dua cov kab mob thiab kev fermentation. Txawm li cas los xij, titer ntawm surfactant hauv cov kab lis kev cai yog qis (1.0 g / L), uas ua rau muaj kev cov nyom rau kev tsim khoom loj (Jiao et al., 2017; Wu et al., 2019). Yog li ntawd, cov txheej txheem kev tsim kho caj ces tau siv los txhim kho nws cov biosynthesis. Txawm li cas los xij, nws txoj kev hloov kho engineering nyuaj vim yog qhov loj ntawm operon (~ 25 kb) thiab kev tswj hwm biosynthetic nyuaj ntawm lub kaw lus quorum sensing (Jiao et al., 2017; Wu et al., 2019). Muaj ntau yam kev hloov kho caj ces tau ua tiav hauv cov kab mob Bacillus, feem ntau yog tsom mus rau kev nce ntxiv ntawm surfactin los ntawm kev hloov tus txhawb nqa (srfA operon), ua rau cov surfactin xa tawm protein YerP ntau dhau thiab cov yam ntxwv tswj hwm ComX thiab PhrC (Jiao et al., 2017). Txawm li cas los xij, cov txheej txheem kev tsim kho caj ces no tsuas yog ua tiav ib lossis ob peb qhov kev hloov kho caj ces thiab tseem tsis tau mus txog kev tsim khoom lag luam. Yog li ntawd, kev kawm ntxiv txog cov txheej txheem kev ua kom zoo raws li kev paub yog qhov tsim nyog.
Cov kev tshawb fawb txog kev puas tsuaj ntawm PAH feem ntau yog ua nyob rau hauv cov chaw kuaj mob ib txwm muaj. Txawm li cas los xij, ntawm cov chaw muaj kuab paug lossis nyob rau hauv cov chaw muaj kuab paug, ntau yam abiotic thiab biotic yam (kub, pH, oxygen, muaj cov as-ham, substrate bioavailability, lwm yam xenobiotics, kev txwv tsis pub muaj cov khoom kawg, thiab lwm yam) tau pom tias hloov pauv thiab cuam tshuam rau lub peev xwm puas tsuaj ntawm cov kab mob me me.
Kub muaj feem cuam tshuam loj heev rau PAH biodegradation. Thaum kub nce ntxiv, qhov concentration ntawm cov pa oxygen yaj txo qis, uas cuam tshuam rau cov metabolism ntawm cov kab mob aerobic, vim tias lawv xav tau cov pa oxygen molecular ua ib qho ntawm cov substrates rau oxygenases uas ua cov hydroxylation lossis ring cleavage reactions. Nws feem ntau sau tseg tias kub siab hloov cov niam txiv PAHs mus rau hauv cov tshuaj lom ntau dua, yog li inhibiting biodegradation (Muller et al., 1998).
Tau sau tseg tias ntau qhov chaw muaj kuab paug PAH muaj cov nqi pH siab heev, xws li cov chaw tso dej kua qaub hauv av uas muaj kuab paug (pH 1–4) thiab cov chaw ua roj av/cov thee uas muaj kuab paug nrog alkaline leachate (pH 8–12). Cov xwm txheej no tuaj yeem cuam tshuam rau cov txheej txheem biodegradation. Yog li ntawd, ua ntej siv cov kab mob me me rau kev kho bioremediation, nws raug pom zoo kom kho pH los ntawm kev ntxiv cov tshuaj tsim nyog (nrog qhov nruab nrab mus rau qis heev oxidation-reduction peev xwm) xws li ammonium sulfate lossis ammonium nitrate rau cov av alkaline lossis liming nrog calcium carbonate lossis magnesium carbonate rau cov chaw acidic (Bowlen et al. 1995; Gupta thiab Sar 2020).
Kev muab pa oxygen rau thaj chaw uas raug cuam tshuam yog qhov txwv tsis pub PAH biodegradation. Vim yog cov xwm txheej redox ntawm ib puag ncig, cov txheej txheem bioremediation hauv situ feem ntau xav tau kev qhia pa oxygen los ntawm cov chaw sab nraud (tilling, air sparging, thiab ntxiv tshuaj) (Pardieck et al., 1992). Odenkranz et al. (1996) tau qhia tias kev ntxiv magnesium peroxide (ib qho tshuaj oxygen tso tawm) rau hauv cov dej khib nyiab uas muaj kuab paug tuaj yeem ua rau cov tshuaj BTEX bioremediate zoo. Lwm txoj kev tshawb fawb tau tshawb nrhiav qhov kev puas tsuaj ntawm phenol thiab BTEX hauv cov dej khib nyiab uas muaj kuab paug los ntawm kev txhaj tshuaj sodium nitrate thiab tsim cov qhov dej rho tawm kom ua tiav bioremediation zoo (Bewley thiab Webb, 2001).