Screening+of+a+Novel+Bioflocculant-producing+Strain+and+Research+on+Its+Flocculation

1998phasewasmeasuredwithaspec-trophotometerat550nm．AcontroIexperimentwithoutbioflocculantwasalsomeasuredbythesamemethod．Flocculatingactivitywascalculatedus．ingthefollowingequation：Flocculatingactivity(FA％)=(ODc-0D)／0Dcxl00(1)Where。ODisopticaldensityofsampleat550nm：ODcreferstoopti-caldensityofcontrolat550nm．ForinvestigatingtheefectofDHontheflocculatingactivity，thepHOfthekaolinsuspensionwasadjustedusing1mol／LofHClorNaOH．Theef．fectoftemperaturewasstudiedusingthekaolinsuspensionandthecrudebioflocculant，thetemperatureofwhichwasadjustedtoadefinitevalue．Distribution。recoveryandpurifica-tionofthebioflocculantCulturebroth(5m1)wascen．trifugedat8000r／minfor20min．Thesupernatantwascollected．Thepre．cipitatedcellswerewashedtwicewithdistilledwater，andthenresuspendedin5mIdistilledwater．Flocculatingactivityoftheculturebroth，super—natantandcelIsuspensionweretest．ed，respectively．BiOfIOCcUIanlwasisolatedandpurifiedaccordingtothemethodde．scribedbyYokoietat．ChemicalanalysisofbIofIOccuIantTotalsugarwasmeasuredbythephenolsulfuricacidmethod[11]．usingglucoseasastandard．Uronicacidsweremeasuredbythecarbazolesul—furicacidmethod[．usinggalacturonicacidasastandard．Aminosugarsweremeasuredaccordinf．．qtotheEson·Morganmethod[13]。usingglucos—amineasastandard．TheIRspectrumofthebioflocculantwasobtainedusinganAVATAR360IRspectrophotome．ter(Nikolet，America)．Forsugarcompositionanalysis，thepurifiedbioflocculantf10mg)washydrolyzedwith1mlOf2mol／Ltrifluo-roaceticacidat1OO℃insealedtubesfor8h．Thesolutionwasdriedandthentrimethylsilylationaccordingtotheme-thoddescribedasLIe“i．ThesugarderivativeswereanalyzedbyaHewlett—Packard6890gaschromato-graph(GC)equippedwitha5973Nmassspectrometrydetector(MS)anda3OmHP一5capillarycolumnf0．25mminsidediameter，0．25umf¨mthickness)．Theinjectoranddetectortemperatureswere250and280oCre-spectively．Thecarriergaswasheliumataflowrateof1mI／min．ResultsandAnalysisIdentificationofthebacteriumThestrainT-11wasgram．nega．five，rod-shaped，non—flagellum，andnon-motile．Thecolonywitharoundedshapeandasmoothedg