Functional genes based analysis of sulfur-oxidizing bacteria community in sulfide removing bioreactor

Sulfur-oxidizing bacteria (SOB) are the main microorganisms that participate in the bioremediation of sulfide-rich wastewater. To reveal the SOB community structure and determine which members of SOB contribute to the sulfide oxidation in a sulfide-rich cloth printing and dyeing wastewater treatment plant, specific primer pairs dsrA 625F/877R, soxB 704F/1199R, and sqr 473F/982R based on the SOB functional genes encoding dissimilatory sulfite reductase, sulfate thioesterase/thiohydrolase, and sulfide: quinone oxidoreductase were designed. The restriction fragment length polymorphism analysis showed that the diversity indices and the abundance of each OTU have no significant changes after time, which suggested the SOB community in the sulfide removing bioreactor have high steady phylogenetic analysis of functional gene-based clone libraries detected the SOB from Chlorobia, alpha-proteobacteria, beta-proteobacteria, and gamma-proteobacteria. The combined clone library showed the presence of dominant members of the SOB species closely related to families Halothiobacillaceae (17%), Hydrogenophilaceae (14%), and Rhodocyclaceae (13%), which may contribute to the sulfide oxidation in wastewater treatment process. This work provides a precise understanding of SOB microbial community within sulfide removing bioreactor, and the result gives assistance for the optimization of the treatment systems for sulfide biological degradation.