低温沼气发酵产酸菌的分离鉴定及发酵特性研究

StudyonIsolationandFermentationCharacteristicsofAcidogenesfortheBiogasFermentationatLowTemperatureAbstractBiogasasalow-carboneconomyhasbecomeanimportantpartofourenergy,withaverybroadprospectsfordevelopment．IncoldregionsofnorthernChina，winterislongandlowtemperatures．Biogasdigestertanktemperatureistoolowresultthatperiodoffermentationstartislong，gasproductionlack，andevenfrostbitedigesterCannotproductgas，whichbecameamajorfactorrestrictingChina’Snorthernhouseholdbiogasdevelopment．Acidogenesplayanimportantroleintheprocessofbiogasfermentation，acidogenesdecomposeorganicmatterproducedVFAisasimpleprecursorsubstancebymethanogensusedcarbon．Therefore，researchingtheacidogenesoflowtemperaturebiogasfermentationhaspracticalsignificance．Thisthesisisseparatedtheacidogenesfromthebiogasdigestertank，whichhaslowtemperatureandhigh-acidstrains，studiedphysiologicalbiochemicalcharacteristicsandacidproductionfeatures，andextractedDNAofstrains，makedamplificationandsequencingwhichbasedon16SrDNA，determinedthegenusandmakedphylogeneticanalysis．Moreover,addingacidproducingStl'8i璐tobiogasfermentationsimulationdevicemakedsimulatedfermentationatlOWtemperature．Theresultsshowedthatthreeheightactiveacid-producingbacteriaatlowtemperaturewerescreenedfromthe16acid-producingbacteriawhichisolated．PhylogeneticanalysisshowedthatthestrainFJ一8isPseudomonas，FJ-15isShewanella，FJ．16isPseudomonas．ThestrainsisproducedVFAmainlyaceticacidandlacticacidduringliquidfermentation．Thereisnoformicacidproducedinsolidstatefermentation．Moreover,theacidpropertiesofstrainsaffectedbytemperature，andthereisstrongestacidproductionunderthestrainsoptimumgrowthtemperature．FJ-8producedacidisthestrongestofthreestrains．Analogfermentationresultsshowedthat：gasproductionincreasedafteraddingacidproducingstrainstobiogasfermentationsimulationdevice，andthestartoffermentationtimeandcycletime，reachthemaximumgasproductioninadvance．Keywords：Biogas；Lowtemperature；Acidogenes；16SrDNA；Directedby：Prof．DUANKaihongKopIicantforMasterdegree：ZHANG№i(FmnmtationEngi