Research The Succession Of Functional Microbial Community Which Participate In C And N Cycle During The Composting

High temperature aerobic composting is one of the effective way to deal with livestock and poultry manure and other agricultural waste. Livestock and poultry manure as nitrogen(N) source participates in the N metabolism and other cellulose as carbon(C)source takes part in the C cycle.This experiment design two types high temperature aerobic composting were divided into A and B pile with cattle manure and rice straw, the initial conditions of this two piles were the same. Pile A is the blank pile, however pile B dealt with inoculant DN-1. Using PCR-DGGE technology to amplify the functional genes(C cycle: beta-glucoside hydrolase gene family GH1, GH3 B, GH3E;N cycle: amo A, nos Z), design functional marker gene general degenerate primers to study the functional microbial community structure changes of C,N metabolism during the composting. At the same time we determine temperature, total carbon, total N, NO3--N, NH4+-N, the degradation rate of cellulose, carboxymethyl cellulose(CMC) and beta-glucosidase enzyme activity, aimed to understand correlation about enzyme activity and physicochemical and microbial dynamic changes during composting. The results are as follows:1 Pile A : 0~3d was the initial stage, 3~18d was thermophilic stage, the highest temperature reached 59 ℃ on day 10, 18~28d was the cooling stage, after 28 d was maturation stage. pile B:0~2d was the initial stage, 2~22d was thermophilic stage, the highest temperature reached 70 ℃in 5d, 22~28d was the cooling stage, after 28 d was manuration stage. pile A: on the 31 d, total C content was 346.5g/kg, the N content was 18.5g/kg, C/N was 19.5, NH4+-N was 0.28g/kg, NO3--N was 1.35g/kg, NH4+-N/NO3--N was 0.34, the rate of cellulose degradation was 31.27%. pile B:the total C content was 360.8g/kg, the N content was 19.4g/kg, C/N was 18.5, NH4+-N was0.19g/kg, NO3--N was 1.43g/kg, NH4+-N/NO3--N was 0.13, the degradation rate of cellulose was62.57%. Addition of exogenous agents can promote the core temperature and increase the degradation rate of cellulose,improve the composting process.2 The peak of CMC enzyme activity about pile A and B were 26 d 12.44U/L and 12 d 14.81U/L respectively. At the end of the compost, CMC enzyme activity about pile A and B to a minimum,as 6.43U/L and 6.71U/L respectively. The peak of beta-glucosidase enzyme activity about pile A and B were 20 d 0.64U/L and 12 d 0.66U/L respectively, At the 8d in the compost, two kinds treatment of beta-glucosidase enzyme activity is reduced to the lowest were 0.45U/L and 0.48U/L.From the C cycle, pile A the microbial diversity which containing beta-glucoside genes ishigher than that of pile B. The GH3 family of fungal diversity is higher than that of the GH1 family and the GH3 family of bacteria. Compared with bacterial the ability of degradation of cellulose, fungi is better. GH1, GH3 family of bacteria play a major role in the degradation of cellulose at 0~8d, the dominant bacteria is Bacillus subtilis, Streptomyces, cellvibrio gilvus. In the later stage of composting, GH3 fungal family takes the main advantage of cellulose degradation bacteria, dominant strain is Trichoderma and Aspergillus. From the cluster analysis,GH1 family B5, B6 Lane similar to 72%. The GH3 family of bacteria A2,A4 lane, similar to the rate of 68%, showed high similarity in pile A during the high temperature period. The GH3 family of fungi B5, B6 lane with high similarity of 67%.3 In the process of the composting, microbial diversity of denitrifying bacteria was higher than that of nitrifying bacteria, microbial diversity in pile A was higher than that in pile B. From the cluster analysis, denitrifying bacteria B4, B6 lane was similar to71%, show that the later stage of thermophilic of denitrifying bacteria in the pile B with the most similar community composition.The majority of compost sample concentrates in the end of the first principal component, pile A showed the denitrifying bacterial community structure is similar in composting. The dominant denitrifying bacteria in the composting is Pseudomonas. The similarity of nitrifying bacteria DGGE map of A6 and B1 Lane reached 70%, showed that the community structure of nitrifying bacteria was similar. The dominant bacteria of nitrifying bacteria in the composting process is Sinorhizobium fredii and Nitrosospira multiformis.