Application of PCR-DGGE to resolve microbial diversity in bio-hydrogen producing reactor

To reveal microbial diversity of anaerobic activated sludge in bio-hydrogen producing reactor, sludge in different period were sampled and their genomic DNA of microbial community was extracted directly. After purification of the genomic DNA using DNA gel recovery kit, the 16S rRNA genes (V3 region) were amplified by using the universal primers (F338GC and R534). The result of agarose gel (2%) electrophoresis show that the PCR products were about 200bp. These amplified DNA fragments were separated by denaturing gradient gel electrophoresis (DGGE) with the denaturant (urea and formamide) from 30% to 60%. The profile of DGGE show that different sludge had the different bands' patterns. In the profiles of DGGE, there exist some common bands in all sludge samples, which indicate that some kinds of microorganisms exist in each period. On the other hand, the specific bands in some sludge show that different period had their own specific microorganisms. Dynamics of community structure and amount of dominant populations were responsible to different period. Shift of microbial diversity correspond to period of running reactor, microbial diversity increased before it decreased. Similarity between communities gradually increased, speed of shift gradually decreased in succession. Finally, microbial climax community made up of specific populations was formed.