交大微生物课件lecture13-2metabolic diversity营养通过氧化无机物而能量

Lecture13-2MetabolicLecture13-2MetabolicDiversityChapter17BROCKBIOLOGYOFSchoolofLifeScienceandBiotechnologyShanghaiJiaoTongUniversity Chemolithotrophy:energyfromtheoxidationofinorganicelectrondonorsChemolithotrophs:obtainenergyfromtheoxidationofinorganiccompounds化能无机营养生物:通过氧化无机物而获得能量ShanghaiJiaoTongAutotrophicorAutotrophicchemolithotrophsobtaintheircarbonfromMixotrophicchemolithotrophs:obtainenergyformaninorganiccompoundbutrequireanorganiccompoundascarbonsource化能无机异养营养生物:能量来自无机物,但碳源来自有机物ShanghaiJiaoTongInorganicelectrondonorsandenergetics无机电子供体p.548ATPformationoxidationofinorganiccompoundsATP的Hydrogenoxidation/reducedsulfurcompoundsoxidation/oxidation/CarbonsourcesFromtheorganiccompoundReducingpowerforCO2fixation:ReverseelectronreactionsShanghaiJiaoTongHydrogenOxidationEnergeticsofH2H2+1/2O2H2OG0’=-catalyzedbyhydrogenase.AutotrophyinH2Mosthydrogenbacteriacanalsogrowaschemoorganotrophs,whengrowingchemolithotrophicallytheyfixCO2bytheCalvin Figure:17-NeedNeedO2asSomeH2bacteriahaveonlythemembrane-boundhydrogenase,andintheseorganismsreducingpowersynthesisoccursfromreverseelectronflow.Twohydrogenases:themembrane-boundhydrogenaseisinvolvedinenergeticswhilethecyto smichydrogenasemakesNADHfortheCalvintoformationofaproton ShanghaiJiaoTongOxidationofreducedShanghaiJiaoTongCompoundsusedaselectrondonors:hydrogensulfide(H2S),elementalsulfur(S0),andthiosulfate(S2O3).Thefinalproductofsulfuroxidationinmostcasesissulfate(SO42-).Figure:17-NeedNeedO2asElectronsfromsulfurcompoundsfeedintotheelectrontransportchaintodriveaprotonmotive ;NADHmustbemadebyreverseelectronflow.通过电子传递链产生质子动势;通过反向电子生ShanghaiJiaoTongIron TheaerobicoxidationofironfromtheferrousFe2+toferric(Fe3+)stateisanenergy-yieldingreactionforsomeprokaryotes:iron-oxidizingbacteria.铁氧化细菌:有氧条Fe2+canbeoxidizedunderanoxicconditionsbycertainanoxygenicphototrophicbacteria:Fe2+isusedinthiscasenotasanelectrondonorinenergymetabolism,butasanelectrondonorforCO2reduction(autotrophy非产氧光合细菌氧化亚铁固定CO2的电子供体而非能量代谢的NeedO2as

Fig.17.30ElectronflowduringFe2+ElectronstravelashortelectrontransportchainresultinginthereductionofO2toReducingpowertodrivetheCalvincyclecomesfromreactionsofreverseelectronflow.13.12NitrifyingShanghaiJiaoTong13.12NitrifyingInorganicnitrogencompounds(NH3andNO2-)areoxidizedaerobicallybythenitrifyingbacteria硝化细菌(好氧)氧化无机氮化合Nitrifyingbacteria:Nitrosofyers(Nitrosomonas)oxidizeammoniatonitrite(NO2)-亚硝化细(亚硝化单胞菌属Nitrobacteroxidizenitritetonitrate(NO3-硝化细Charactersofnitrifyingbacteria:LowATPyieldandslowCalvincycleforCO2MostnitriteoxidizersarealsoFig.17.32electronflowinNH3isoxidizedbyammoniamonooxygenasethatproducesNH2OHand ethen.2NH2OHtoNO.2NeedO2as

亚硝化菌:在氨单加氧酶作用下氨被氧化为羟胺和水,然后羟胺AMO,Ammoniamonooxygenase氨单加氧酶;HAO,hydroxylamine e羟胺氧还酶;Q,yShanghaiJiaoTongyFig.17.33Oxidationofnitritetonitratebynitrite-oxidizingbacteria：itemploy etooxidizenitritetonitrate,withelectronstravelingaveryshortelectrontransportchaintotheterminaloxidase.硝化细NeedO2as菌:由亚NeedO2as酸氧化为硝酸NOR, ShanghaiJiaoTongAnoxicAmmoniaOxidation-Anammox(foranoxicammoniaoxidation厌氧的氨氧化过NH4++NO2-N2+2H2O,G0’=-Ammonia(electrondonor)areoxidizedtoN2byusingnitriteelectronSignificanceforagriculture:Ammoniaarenotstableunderanoxicforenvironmentalprotection:abeneficialprocessintheofanoxicShanghaiJiaoTongTheanammoxisanAutotrophy:TheanammoxorganismcangrowwithCO2assolecarbonsourceandusesnitriteaselectrondonortoproducecellmaterial:CO2+2NO2-TheanammoxIndustrialapplicationofShanghaiJiaoTongTheAnaerobicWayofLifeAnaerobicrespiration厌氧呼吸Anaerobic TerminalelectronacceptorsforrespirationFe3(ferricironreduction铁还原-

Fumarate(organicelectronSO42(sulfatereduction硫酸还原((a)chemoorganotrophicrespiratorymetabolism:aerobicandanaerobicrespiration.EnergyEnergyFigure17.35ExamplesofanaerobicrespirationsBecausetheO2/H2Ocoupleisthemostelectropositive,moreenergyisavailablewhenO2isusedthanwhenanotherelectronacceptorisused.ShanghaiJiaoTongAssimilativeanddissimilativeTheuseofthesecompoundsaselectronacceptorsforenergymetabolisminanaerobicrespirationisdissimilativeWhenaninorganiccompound(NO3-,SO42-,orCO2)isforuseasanutrientsource,itissaidtobeassimilated,thereductionprocessisassimilativemetabolism无机化合物还ShanghaiJiaoTongNitratereductionandDenitrification:Nitrateisreducedtogaseousnitrogen(nitrousoxideN2O,nitricoxideNOandnitrogengasN2)4Fig.17.36Stepsinthedissimilativereductionofnitrate.AllenzymesinvolvedarederepressedbyanoxicconditionsSomeprokaryotesareknownthatcanreduceNO3-toNH+indissimilativemetabolism.所有这些酶4ShanghaiJiaoTong4differentDenitrification:Asalternativeelectronacceptors,nitrateisreducedtonitrousoxideN2O)nitricoxideNOandN2反硝化硝酸作为电子受Nitrification:useinorganicnitrogencompoundsaselectrondonors.Ammoniaandnitriteareoxidizedaerobicallybythechemolithotrophicnitrifyingbacteria硝化氨或亚硝酸等无机氮化合物作为电子供体NitrogenfixationuseofN2asabiosyntheticnitrogensource固氮作用:Assimilativemetabolismofnitrate:nitrateisreducedtoammoniaforuseasanutrientsource.硝酸盐的同化还原代谢：硝酸被还原为氨而作ShanghaiJiaoTongSulfatereduction硫还Severalinorganicsulfurcompoundsareimportantelectronacceptorsinanaerobicrespirationdissimilative)ShanghaiJiaoTongFigure17.38assimilativeanddissimilativesulfateInassimilativesulfatereduction,theH2Sformedis yconvertedintoorganicsulfurcompounds,butindissimilativesulfatereduction,theH2Sisexcreted区分同化过程的还原:硫的去向ShanghaiJiaoTong

p.564sectionMethanogens-agroupofstrictlyanaerobicArchaea产甲ReductionofCO2toCH4isH2H2+CO2