Speaker: Professor Anna Schnürer, Department of Microbiology, Bio Centrum, Swedish University of Agricultural sciences, Uppsala Sweden
Location: Cassie 2.33
Time/Date: 1st June 2012, 13:00 - 14:00
Protein rich materials are due to their high energy content excellent materials for biogas production. Furthermore, during the anaerobic degradation of proteins ammonia is released, giving a high fertilizing value of the digestate. Unfortunately, ammonia also causes inhibitory effects on the microbial consortia active in the biogas processes, resulting in instability problems and decreasing methane yields. Several studies have considered strategies to improve process operation with protein rich materials, e.g. dilution of substrate, use of additives, change of operational temperature etc. In addition, acclimatisation has been reported to increase the tolerance and retain microbial viability at ammonia concentrations far exceeding the initial inhibitory concentrations. The “ammonia problem” has been intensively studied for several years with the overall goal to generate microbial knowledge needed for stable management of biogas processes with nitrogen-rich materials. Specifically we have focused on the so called syntrophic acetate oxidizing bacteria and their interaction with hydrogenotrophic methanogens, and we have shown that high ammonia concentrations is an important factor for regulating the growth and activity of these microorganisms.
More specifically we have studied the presence and abundance of syntrophic acetate-oxidizing organisms and methanogens in different biogas reactors, both at lab and large scale, by the use of combined cultivation and molecular approaches (qPCR, Cloning, TRLP). Furthermore, the importance of syntrophicacetate oxidation for process stability has been studied by using bioaugmentation as a possible method to decrease the adaptation period of biogas reactors operating at graduallyincreased ammonia. Through genome analysis and protein analysis we might also have revealed the first clues to the acetate oxidizing ability of SAOB.
Published: 29th May 2012