[Analysis of microbial community variation in the domestication process of sludge in a sulfate-reducing reactor]

The variations of microbial community in the sludge of sulfate-reducing UASB during domestication period were analyzed by PCR-DGGE technique. The results showed that the diversity of microbial community was strongly related to the sulfate reduction and COD removal performance. The sulfate reduction rate of the reactor was about 95% when the Shannon index of microbial community was higher than 3.45. The preponderant bands in DGGE figure were excised and cloned, and the sequencing analysis indicated there were Firmicutes, Proteobacteria, Deinococcus-Thermus and Chloroflexi in the sludge, which accounted for 50.0%, 28.6% 14.3% and 7.1% of the total sequences of samples, respectively. The anaerobic fermentative bacteria of Clostridium sp. were predominant in the whole domestication period, but the predominant species was changing. Some anaerobic bacteria like Chloroflexi sp. and Geopsychrobacter sp. were detected to be dominant species, which then disappeared along with further domestication, but anaerobic bacteria Geobacter sp. became gradually predominant in the domestication process. Species of Desulfovibrio sp. were detected to be predominant only in the last two phases of domestication.