Microbiology of phase-separated reactor systems for biomethanation at high temperatures (55 - 75°C) [article]

Antje Rademacher, Technische Universität Berlin, Technische Universität Berlin
In recent years, the number of agricultural biogas plants, as a means of generation of renewable energy, has risen constantly in Germany. In 2011, 7,215 agricultural biogas plants were operated with a total installed electric capacity of 2,904 MW. Thermophilic temperatures and a spatial separation of the process phases hydrolysis and acetogenesis from methanogenesis are known strategies for improving and stabilizing biogas production. A deep understanding of the underlying bacterial and
more » ... cterial and archaeal community involved in the breakdown of plant-derived biomass and the subsequent production of methane in phase-separated, thermophilic systems is of major importance for further improvement. Pursuant to this aim, phase-separated leach-bed biogas systems, which were supplied with rye silage and straw lasting for 21 days, were analyzed. Each system consisted of a leach-bed reactor (LBR), whose temperature was increased stepwise from 55 to 75 °C, a leachate storage reactor and a downstream anaerobic filter reactor, whose temperature remained at 55 °C throughout the experiment. Various culture-independent methods were used for the characterization, quantification and monitoring of the microbial community within these biogas systems. The culture-independent methods were based on the genetic information of cells, applying gene library construction, TRFLP fingerprinting, metagenomic and qPCR analyses and on the microscopical quantification of intact, but not cultivated cells. The present study revealed the composition and dynamics of the microbial community and their genetic potential for carbohydrate degradation in two-phase leach-bed biogas systems at thermophilic to hyperthermophilic temperatures. Temperatures of 55 to 60 °C in the LBR had a positive effect on the microbial community responsible for the production of biogas, leading to the best reactor performance. Furthermore, the results indicated potentially process-relevant bacteria and glycoside hydrolases, which may serve as target for the monitoring of thermophilic b [...]
doi:10.14279/depositonce-3791 fatcat:fnbv7dra5bbgfntyyiny4jhmky