一株产絮凝剂菌株的特性与其培养条件优化

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1、万方数据剂的相关特性研究表明：该微生物絮凝剂具有较佳的耐热性和耐酸碱性，从pH(4～13)和温度(4～60。C)均具有较佳的絮凝率，具有较广的应用范围，这归功于微生物絮凝剂的主要组分多糖和极性官能团。通过荧光定量PCR方法建立了甲基营养型芽孢杆菌中的絮凝相关基因katE，pepT，sacA及scrR和菌株絮凝活性之间的关系。此外，利用Zeta电位，初步探索了微生物絮凝过程中涉及到的两步沉淀机理(电中性机理和架桥机理)。本论文也证明了微生物絮凝剂MBF412的潜在工业应用价值。关键词：甲基营养型芽孢杆菌微生物絮凝剂响应面优化基因表达絮凝机理II万方数据T1‘一‘。一‘

2、n一一⋯ldentincationandCharacterizationofanovelBacillusmethylotrophicuswithhighflocculatingactivityABSTRACTInthisstudy,anovelbioflocculant—producingstrainwasderivedBacillusmethylotrophicusby16SrDNAandgyraseBsequencinganalysis，aswellasmorpHological，pHysiologicalandbiochemicalcharacterizati

3、ons．Thecomponentofbioflocculant(i．e．，MBF412)secretedbystrainC412iscomposedof57．3％polysaccharidesand1．7％protein．TheresultsofGPCindicatedthattheaveragemolecularweightofthebioflocculantwas3．47x10’Jm01．．Thebioflocculantproduction(4．25gm)wasassociatedwiththebacterialgrowthprocess，andthemaxi

4、mumflocculatingactivityof98．27％wereachievedusinganoptimizedculturemediumbyresponsesurfacemethodologycontaining(perliter)solublestarch(19．73g)，beefextract(1．35g)，(1蛆1--14)2S04(3．05g)，NaCl(Ig)，KH2P04(2g)，K2HP04(5g)，andMgS04(O．05g)atpH7．63．BatchfermentationofstrainC412inhigh—celldensitycu

5、lturesshowedshortergenerationtimesina1．5Lfermentor(2～6h)thaninashake—flask(13+-17h)．Thissignificantdecreaseoffersacost--effectivemethodforlarge·-scalebioflocculantproduction．Thebioflocculantisthermostableoverabroadtemperaturerange(4oCto60oC)andhaswidepHreceptivity(4to13)，whichmaybeattr

6、ibutedtoitsmaincomponents，namely,polysaccharidesandpolarfunctionalgroups．Relativeflocculent—geneexpressioninnovelB．methylotrophicusC412wasstudiedbyquantitativereversetranscriptionPCR．TherelationshipbetweentheexpressionlevelsofkatE，pepT,andscrRandIII万方数据flocculatingactivitywasestablishe

7、d．Furthermore，atwo—stepflocculationmechanism(i．e．，chargeneutralizationandbridgingmechanism)wasproposedforthesettlementprocessbasedonzetapotentialanalysis．ThisstudyalsodemonstratedthepotentialofMBF412fortreatingindustrialwastewater．KEYWORDS：BacillusmethylotrophicusBioflocculantRespons