Study On Isolation And Fermentation Characteristics Of Acidogenes For The Biogas Fermentation At Low Temperature

Biogas as a low-carbon economy has become an important part of our energy, with a very broad prospects for development. In cold regions of northern China, winter is long and low temperatures. Biogas digester tank temperature is too low result that period of fermentation start is long, gas production lack, and even frostbite digester can not product gas, which became a major factor restricting China’s northern household biogas development. Acidogenes play an important role in the process of biogas fermentation, acidogenes decompose organic matter produced VFA is a simple precursor substance by methanogens used carbon. Therefore, researching the acidogenes of low temperature biogas fermentation has practical significance.This thesis is separated the acidogenes from the biogas digester tank, which has low temperature and high-acid strains,studied physiological biochemical characteristics and acid production features, and extracted DNA of strains, maked amplification and sequencing which based on16S rDNA, determined the genus and maked phylogenetic analysis. Moreover, adding acid producing strains to biogas fermentation simulation device maked simulated fermentation at low temperature.The results showed that three height active acid-producing bacteria at low temperature were screened from the16acid-producing bacteria which isolated. Phylogenetic analysis showed that the strain FJ-8is Pseudomonas, FJ-15is Shewanella, FJ-16is Pseudomonas. The strains is produced VFA mainly acetic acid and lactic acid during liquid fermentation. There is no formic acid produced in solid state fermentation. Moreover, the acid properties of strains affected by temperature, and there is strongest acid production under the strains optimum growth temperature. FJ-8produced acid is the strongest of three strains. Analog fermentation results showed that:gas production increased after adding acid producing strains to biogas fermentation simulation device, and the start of fermentation time and cycle time, reach the maximum gas production in advance.