Bacterial and archeal dynamics of a labscale HYBRID gas fermentation bioreactor fed with CO and H.

16s rDNA-based methods were used in order to identify the dynamics of microbial profiles in a HYBRID gas fermentation bio-methanization reactor. The effects of various H and CO ratios on microbial community were investigated. The HYBRID gas fermentation reactor was composed of granular anaerobic seed and the system fed with only H and CO gases. No additional organic material and trace element was fed during the throughout the experiments; thus, the microbial diversity was directly related to production of methane. The dynamics of the microbial communities were investigated with DGGE and real-time PCR analysis. The results showed that members were more dominated than members in the system. DGGE results indicated that sp., , sp., and were the most prominent methanogens depending on different H/CO ratios. DGGE profiles suggested that hydrogenotrophic and acetoclastic species were responsible for the production of methane. The survival of syntrophic bacteria and acetoclastic methanogens was attributed to their utilization of organic materials provided by lysis. To the best of our knowledge, this is the first microbial profile detection study in a hybrid bioreactor system operated with only pure hydrogen and carbon dioxide.