Application of PCR-DGGE to analysis the microbial community diversity in biological biofilm reactor

In order to reveal microbial community structure diversity of bioflim reactor processing simulation domestic wastewater, the start-up initial stage and operation later stage biofilm from porcelain plate sliding surface, porcelain plate coarse surface, white rubber sheet and black experiment countertops were taken and the genomic DNA of microbial communities were extracted by the method of cell lysis. PCR-amplified 16S rRNA which using the universal primers and denaturing gradient gel electrophoresis (DGGE) were applied to obtain the DNA fingerprint profile of the microbial communities. The results showed that similarity between microbial communities of different blocking material were up to 78.3%, the lowest of 41.4%, the profile of DGGE showed that different biofilm samples had both different microbial species and common species. However, the biofilm community structure of both start-up initial stage and operation later stage are maintaining stability and the succession was obvious. In addition, part of the biofilm microbial community of dominant bacteria was analyzed through cloning sequencing and phylogenetic analysis. Five bacterial 16S rDNA sequences were identified and with a homology over than 97% when compared with the bacteria of Clostridia bacterium sp., Clostridium sp. and Brevundimonas sp.. These dominant microorganisms played important roles in the removal of organic pollutants in the bioflim system.