A Microbial Community Capable Of Biogas Production And It's Application In Anaerobic Fermentation Of Cattle Manure

A microbial community capable of biogas production with genetic stability was enriched from biogas slurry with the method of limited culture at 35℃. The microbial diversity was detected using 16S rDNA clone technology. The optimum cultural conditions of microbial community were investigated with the methods of single factor analysis and orthogonal test analysis. Effects of different quantities of inoculation, materiel concentrations on biogas production were investigated in the fermentation system of 20L. The effects of initial concentration of nitrogen, phosphorus and potassium increased to one, twice and trible times compared with control were researched on biogas production.The limited culture results showed that biogas production of each subculture was stabile after 26 subcultures, and the maximum daily biogas production and methane production was 1.6 m3·m-3·d-1 and 1.5 m3·m-3·d-1 under the condition of 100 mL volume of fermentation system, 5% total solid and 10% of inoculation of microbial community. The results of single factor analysis and orthogonal test analysis showed that the optimum cultural conditions of microbial community for biogas production using the cattle manure as the material were 5% of inoculation quantity, 10% of concentration of substrate,natural pH and temperature 35℃.The microbial diversity of microbial community was analyzed using 16S rDNA molecular clone technology. The results showed that archaebacteria group was composed with Methanoculleus sp., Methanosarcina mazeii, methanogenic archaeon, Euryarchaeote. Bacterial group was composed with Peptococcaceae bacterium, Bacteroides sp., Eubacterium, Fibrobacteres bacterium,Pseudomonas sp., Clostridium sp., Aminobacterium colombiense, Selenomonas sp. and uncultured bacterium. Therefore the microbial community was composed of different archaebacteria and eubacteria, it had a high microbial diversity.The results of experiment of diffrernt inoculum quantities showed that the biogas production of treatment of 15% inoculum (V/V) was the highest, and the total methane production was higher 37.4% and 34.5 % compared with treatments of 5% and 10% inoculum. Total biogas production and total methane production of 5% inoculum treatment were higher 3.1% and 11.8% compared with control. The optimum inoculation quantity of scale-up culture is 15% comprehensively considering the biogas production time, the maximum biogas production level, and the total production level of methane. At the same time, the treatment of 10% TS of substrate concentration was the optimum for biogas production.The initial concentration nitrogen, phosphorus, and potassium of feed solution significantly effected biogas production. The total biogas production of the treatment that the total content of nitrogen, phosphorus, and potassium were increased one time more than basic concentration was improved 2.4%, 78.2%, 78.7% compared with basic content treatment, two time treatment and three time treatment, respectively. Futhermore, the methane production of one time content treatment was increased 7.3%, 96.4% and 99.6% compared with other treatments, respectively. The some gas was producted in treatments of twice and trible times more than basis nitrogen, phosphorus, and potassium concentration after inoculated 12 hours, but the methane almost was not detected among the gas ingredients.