Candidatropicalis激光育种技术及其降酚特性研究

《Candidatropicalis激光育种技术及其降酚特性研究》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、2005年12月ABSTRACTAtpresent,thebiologicaltreatmenttechnologyisinthetransitionalperiodfrommixedculturetopureculture．Inthispaper,twostrainstodegradephenolwithhighactivitywe犯isolatedandidentifiedfromacclimatedactivatedsludgebyusingthetraditionalmicroorganismbreedingtechnology．Inbetween,theyeastCa

2、ndidatropicaliswascompletelyinvestigatedforitscharactersofphenoliccompoundsbiodegradation．InordertoenhancethecapacitiesofCtropwalistodegradephenoliccompounds，He-NelaserWasutilizedtoirradiatewild-typeCtropicalis．Theoptimalirradiationparameterswei'eobtainedthroughalotofparallelexperimentsasfol

3、lowing：10roWl0—15min,12．5mWl0-15minandl5roWlorain．Correspondingly,highpositivemutationfrequencywasobtainedinthisrange．Inphenolbiodegradationtests，70positivemutantswithhi【ghphenolbiodegradationpotentialWerescreened．PhenolbiodegradationstabilitieswereinvestigatedandCTM2wasattainedandusedinthef

4、ollowingstudiesforitsforemostbiodagradationpotentialandstability．Becauseofthedefinitiveeffectsofphenolhydroxylaseandcatecholdioxygenaseonphenolmetabolism，theactivitiesofthesetwoerlzymeswereinvestigated．ItshowedtheactivitiesofthesetwoenzymeswerehigherinmutantstrainCTM2thaninthewildstrain,whic

5、hwaspresumablyduet0thelaserirradiation．Thus，thefull-lengthsequenceofphenolhydroxylasegeneWassucecssfullyclonedbyPCRmethodinwildandmutantCtropicalis．respectively．Thecomparisonofaminoacidofphenolhydroxylasebetweenwild-typeslrainandmutantstrainCTM岔illustratedfouraminoacidsweremutatedafterthestr

6、ainWasirradiatedbyHe-Nelaser．Inaddition,heterogenousexpressionofphenolhydroxylasevalidatedthetruththattheenzymeactivityvariedaftercellirradiatedbylaser．Thecharactersofphenol，m-cresoland4一chlorophenolbiodegradationwerecontrastivelystudiedbetweenmutantstrainCTM2anditsparentstrain．Theirmaximump

7、henolbiodegradationswere2000and2600rng／L，andthemaximumspecificgrowthrateswereO．48and0．54I／b,respectively．Besides．thebiodegradationofthewildandmutantstrainswerealSOstudiedindual．substratesystem。respectively．Theexperimentsshowedthattheinhibitionstoee