Enhancement of Microbial Function for a Sulfur Redox Cycle Action in a Sewage Treatment Process Combining an UASB and an Aerobic Filter Reactor

点击翻译按钮获取中文摘要

The structure of microbial community was analyzed on sludge samples taken from the aerobic biofilter reactor by using clone libraries of 16S rRNA genes. Clone similar to Thiobacillus and Thiothrix was counted at 10 and 7, respectively, among 188 clones randomly selected from the libraries. Approximately 7% of DAPI stained total cells in the biofilter sludge hybridized with the probe Thio840 specific for Thiobacillus group. Real-time PCR using SYBR green I was employed with BONE663cF-Thio840R primer set to determine the copy number of 16S rRNA gene originated from Thiobacillus. High concentration of sulfide at 30 mg-S/L in the influent strongly enhanced abundance of the gene of 10^5 copies/ng levels in total DNA extracted from the aerobic biofilter sludge. the diversity of adenosine-5'-phosphosulfate reductase (apsA) genes, which produce a key enzyme for sulfate respiration and are present in all sulfate-respiring prokaryotes (SRPs), in UASB sludge was analyzed by cloning and sequencing techniques. The apsA amino acid sequence-based phylogenetic tree showed that the identified clones belonged to four groups : the sulfate-reducing bacterial group, Syntrophobacteraceae, Thiobacillus and the clone cluster group, distantly related to any previously described apsA clone. Real-time PCR quantification which used the primer sets specific for each of the four apsA gene sequences revealed that Desulfobulbaceae and Desulfovibrionales were the predominant species all of the sulfate-reducing bacteria in the UASB sludge throughout the experimental period. An excellent correlation of apsA gene abundance and behavior was found between the sulfate-reducing bacteria and Thiobacillus, as well as between Syntrophobacteraceae and the unknown apsA clone group.