Chlorinated ethene degrading bioreactor performance
This work focuses on the development of trichloroethylene anaerobic degrading consortium and its molecular biology analysis. Subsequently, through acclimating the anaerobic sludge, a TCE-degrading consortium was enriched in the up-flow anaerobic sludge blanket (UASB) reactor. When TCE concentration was 14.6-73mg/L, the TCE removal efficiencies was 85%-90%. The structure of TCE-degrading consortium was analysed by pyrosequencing and 16S rDNA clone library. Many kinds of fermentation bacteria (such as Petrimonas, Clostridium, Enterobacter and Lactococcus) and Methanosaeta (99.54%) that used acetate as sole carbon source were observed. Importantly, there were three types of dechlorinating bacteria: Dehalobacter, Dehalococcoides, and Geobacter. In addition, we found there was Mesotoga prima MesG1.Ag.4.2 in the consortium which was isolated from a polychlorinated biphenyl (PCB)-dechlorinating enrichment culture from Baltimore Harbor sediments and had a reductive dehalogenase gene-a key enzyme in dehalorespiration. By using Central Composite Design in Response Surface Methodology, the growth conditions of the TCE-degrading consortium were optimised. After optimization, the average removal rate of TCE was 97.71%. In addition, the changes of bacterial diversity and community structure and function were studied by high-throughput sequencing under different operation parameters (hydraulic retention time (HRT), temperature, and pH). The results indicated that the order of effect of operation parameters on the bacterial structure and relative abundance was pH＞HRT＞T.