MONITORING THE BIOGAS PRODUCING ARCHAEA COMMUNITY VIA MOLECULAR BIOLOGICAL METHODS
N. Ács1, Z. Bagi2, E. Kovács2, R. Wirth2, K. L. Kovács1,2
1Institute of Biophysics, Biological Research Centre, Szeged, Hungary,
2Department of Biotechnology, University of Szeged,
Biogas is one of the most promising renewable energy carriers since it has got the potential to produce energy from numerous biomasses, combining the production of green energy with the elimination of hazardous waste streams. Biogas, the main product of the anaerobic digestion (AD) process can be utilized by burning in combined heat and power (CHP) units or after purification it can be treated equivalently to the natural gas.
If we want to enhance the produced biogas yield, or digest unconventional substrates, a deeper understand of the microbial community involved in the fermentation is requisite. This can be achieved with the culture independent methods. These molecular biological tools (TGGE, DGGE, ARDRA, RISA, T-RFLP) are widely applied today.
High protein content substrates are considered toxic for the biogas fermentation due to the high level of ammonia released upon protein degradation. In this study systematic experiments were conducted in 5 litre CSTR (continuous stirred) fermentors, fed wit protein-rich substrates (casein or pig blood).
We selected T-RFLP technique to determine the abundant archaeal microbial groups from the assortment of genomic DNA in the fermentation sample. Fluorescent labeled primers targeting the large subunit of the methyl-coenzyme-M-reductase (mcrA) gene were used to generate the mixed PCR product from the purified gDNA. The restriction endonuclease, RsaI was applied in order to generate the RFLP patterns of the selected samples. We concluded that the unconventional substrate source affected not only the primary consumers (hydrolyzing bacteria) but the archaeal community as well. A significant shift could be observed, confirming the dominant role of the genus Methanoculleus in the conversion of protein-rich material into biogas.
The presented work was supported by the European Union and co-funded by the European Social Fund.
Project numbers: HUSRB/1002/214/041 IPA and HURO/1001/193/2.2.2. CBC.
TÁMOP-4.2.1/B-09/1/KONV-2010-0005 and TÁMOP-4.2.2/B-10/1-2010-0012
