Analysis Of Microbiological Communities Structure In Composting Of Kitchen Waste By PCR-DGGE

Composting is the natural process of the strengthening of microbial degradation and relies on the widely distributed nature of the bacteria, fungi, actinomycetes. Microorganisms are key organisms in the composting systems. So, studying the microbial communities in composting systems is of great importance for technique improvement and efficiency enhancement. However, the traditional techniques of culture and separation technologies for environmental microbiology researches could not satisfy nowaday environmental microbiology researches which require analysis and identification more directly and more exactly. Using molecular thechnologies PCR-DGGE, researchers can study microbes without separation and culture. And more, researchers even can expect direct and exact results of conformation or function of microbial communities.PCR-DGGE analysis was used to study the dynamic succession of bacterial communities during composting of kitchen waste. Composts were sampled during different composting periods, and Physical Chemical Parameters were measured. The Results showed that the final pH was 7.5 and the C/N was 20.04, the pile was insulated and temperatures above 50℃were maintained for 7days. Which was high enough to kill pathogens. After extraction and purification of the genomic DNA from the sample compost, the 16S rRNA genes (V3 region) were amplified by using the bacterial primer pair GC-341F/907R. Then, the amplified 16S rDNA fragments were separated by DGGE. Different DGGE bands appeared during different composting periods. The Cs values of pairwise similarity coefficient were analyzed for samples from composting days (0, 4, 10, 14, 18). The Cs value of micro-ecological structure was the highest in the 4th days, Temperature appears to played a key role in determining the composition of bacteria present at the respective stages of the composting process.Using PCR-DGGE technique and phylogenetic analysis, the thermophilic bacterial communities structure in high-temperature composting of kitchen waste was studied. The composting high-temperature stage (>50℃) time continued 7 days, in this period, sampling stack body and collecting microbial total DNA of the object, 16S rDNA fragments were amplified using universal bacteria primers (GC-341F/907R). The DGGE analysis was carried out on amplification of 16S rDNA. The DGGE twig belt similarity Cs value analysis and cut glue survey order, using order arrange data to carry out same source property analysis, and system phylogenetic tree was established. The analysis results of DGGE and similarity Cs value showed that the composting high temperature stage had more rich bacteria diversity and existed obvious superior community structure change, the analysis results of cut survey order and phylogenetic showed that large part of high temperature stage superior community order arrange Bacillus and Clostridium possessed nearer blood relation.The succession profile of thermophilic fungi and actinomycetes communities during the high temperature stages of kitchen composting were studied by PCR-DGGE. Microbial total DNA was extracted from high temperature stages samples,and the aiming products were successfully amplified from the total DNA by fungal primer pairs(GC-NS7/NS8)and actinomycetes primer pairs(F243/GC-R513),and then were used for DGGE and Cs value analysis.The result showed that both of the thermophilic fungi and actinomycetes of high temperature stages changed similarly, themophilic fungi in high temperature stages of composting can be divided into three phases. The kitchen composting high temperature stage existed obvious superior fungi and actinomycetes communities structure change.