Harmfulalgalblooms(HABs)haveledtoextensiveecologicalandenvironmentalissuesandhugeeconomiclosses.VariousHABcontroltechniqueshavebeendeveloped,andbiologicalmethodshavebeenpaidmoreattention.Algicidalbacteriaisageneraldesignationforbacteriawhichinhibitalgalgrowthinadirectorindirectmanner,andkillordamagethealgalcells.AmetabolitewhichisstronglytoxictothedinoflagellateAlexandriumtamarensewasproducedbystrainDH46ofthealga-lysingbacteriumAlteromonassp.Thecultureconditionswereoptimizedusingasingle-factortestmethod.Factorsincludingcarbonsource,nitrogensource,temperature,initialpHvalue,rotationalspeedandsalinitywerestudied.Theresultsshowedthatthecultivationofthebacteriaat28℃and180rmin-1withinitialpH7and30saltcontcentrationfavoredboththecellgrowthandthelysingeffectofstrainDH46.TheoptimalmediumcompositionforstrainDH46wasdeterminedbymeansofuniformdesignexperimentation,andthemostimportantcomponentsinfluencingthecelldensityweretryptone,yeastextract,solublestarch,NaNO3andMgSO4.Whenthefollowingculturemediumwasused(tryptone14.0g,yeastextract1.63g,solublestarch5.0g,NaNO31.6g,MgSO42.3gin1L),thelargestbacterialdryweight(7.36gL-1)wasobtained,whichwasanenhancementof107%comparedtotheinitialmedium;andthealgallysisratewasashighas98.4%whichincreasednearly10%afteroptimization.
