Screening And Function Of Bacteria To Promote Thermogenesis From Aerobic Fermentation Of Stover

Winter heating in rural areas of northern China is dominated by burning bulk coal with high nitrogen and sulfur content,which produces a lot of air pollution.Recycling the heat generated in the aerobic fermentation(composting)process of straw and other biomass can realize clean heating in rural areas,and solve the problem of a large number of straws burning and abandonment of in the north.In addition,the fermentation process is simple and is not limited by the scale.Therefore,this is an ecological energy use mode suitable for rural areas.The traditional straw aerobic fermentation is for the purpose of obtaining organic fertilizer and does not require high fermentation rate.However,the decomposition efficiency of lignocellulosic biomass with traditional bacterial agents is low.Therefore,it is necessary to isolate and screen specific "thermogenic bacteria" to promote lignocellulosic degradation and apply them to aerobic fermentation thermogenic research.This topic mainly carried out the screening and function research of "thermogenic bacteria" including straw aerobic fermentation starter bacteria and cellulose-degrading bacteria.The main research results and conclusions are as follows:According to the requirements of low temperature start-up and rapid degradation of lignocellulosic and heat resistance by functional bacteria in the main fermentation stage,the pure bacteria and functional bacteria were screened from soil and fermented straw by using transparent circle method,enzyme activity determination and restricted culture method.Two starch degrading bacteria,two hemicellulose-degrading bacteria and one cellulose-degrading bacteria were screened as low temperature starter bacteria,two high temperature resistant cellulose-degrading bacteria and two heat resistant cellulosedegrading bacteria were screened.Molecular biology was used to identify the screened strains as Bacillus.Brevibacillus borstelensis、Chelativorans composti and Ureibacillus thermophilus were the main strains of heat-resistant cellulose-degrading microbial consortium.These strains all grew well in the p H range of 4 ～ 10.The caloric yield of "thermogenic bacteria",which was composed of low temperature starter bacteria and high heat resistant cellulosic degrading bacteria,was 2980.21 k J/kg(DM)after 20 days of fermentation.The heat yield was 2500.99 k J/kg(DM)after 20 d fermentation by heatresistant cellulosic degrading bacteria.In order to evaluate the effect of functional microorganisms on heat production and enhancement during straw aerobic fermentation,fermentation process experiments were carried out.The fermentation temperature can be rapidly increased under low temperature with starter bacteria.The fermentation system with starter bacteria initial temperature of10℃ can reach the maximum temperature of 44.1℃ in 32 h,while the control group without starter bacteria can reach the maximum temperature of 34.3℃ in 32 h.The thermogenic bacteria can effectively improve the thermogenic capacity of aerobic fermentation.The maximum temperature of the thermogenic bacteria in the fermentation system was 51.2℃,and the heat yield was 3104.57 k J/kg.The maximum temperature of the control group was only 45.3℃,and the heat production was about 1/3 of that of the control group.