PCR-based DGGE fingerprinting and identification of methanogens detected in three different types of UASB granules.

Methane is produced by various methanogenic bacteria present in upflow anaerobic sludge blanket (UASB) bioreactors. Methane can be used to predict and improve UASB bioreactor efficiency. The methanogen population in the granules can be influenced by the composition of the substrate. The aim of this study was to fingerprint and identify the methanogens present in three different types of UASB granules that had been used to treat winery, brewery and peach-lye canning effluents. This was done using polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) and DNA sequence analysis. The DGGE fingerprints obtained from the methanogen reference cultures of Methanosaeta concilii, Methanosaeta thermophila, Methanosarcina barkeri, Methanosarcina mazeii and Methanobacterium formicicum were compared to the DGGE profiles of the Archaea in the different granules. The positions of the DGGE bands that did not correspond well to the bands of the known species were sequenced and compared to sequences available on GenBank using the Blastn search option. The aligned DNA sequences were used to construct a phylogenetic tree. Based on the data obtained, a DGGE marker was constructed which was used to provide a quick method to identify the Archaeal members of the microbial consortium in UASB granules.