Methanogens in biogas production from renewable resources--a novel molecular population analysis approach

• Published in: Water science and technology 2008-01, Vol.58 (7), p.1433-1439
• Main Authors: Bauer, C, Korthals, M, Gronauer, A, Lebuhn, M
• Format: Article
• Language: English
• Subjects: Anatomical structures; Biogas; Bioreactors; Bioreactors - microbiology; Cloning; Conformation; Corn silage; DNA; Fens; Methane - biosynthesis; Methanobacteriales - classification; Methanobacteriales - genetics; Methanobacteriales - metabolism; Methanococcales; Methanogenic bacteria; Methanomicrobiales; Methanomicrobiales - classification; Methanomicrobiales - genetics; Methanomicrobiales - metabolism; Methanosaetaceae; Methanosarcinaceae; Methanosarcinaceae - classification; Methanosarcinaceae - genetics; Methanosarcinaceae - metabolism; Molecular structure; Nucleotide sequence; Oryza sativa; PCR; Polymerase Chain Reaction; Polymorphism; Polymorphism, Single-Stranded Conformational; Population structure; Reactors; Renewable resources; Sequences; Sequencing; Soil; Sustainable yield; Zea mays
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2008.514

The population structure of thermo- and mesophilic biogas reactors digesting maize silage as the sole substrate was investigated employing a novel, highly degenerated PCR-primer pair targeting mcrA/mrtA coding for the key enzyme of methanogens. No sequence affiliating with Methanococcales, Methanopyrales, ANME-, rice or fen soil clusters was detected. Direct MeA PCR-cloning results indicated that Methanobacteriales were the most important methanogens in the thermophilic reactors. 57% and 80% of the analysed sequences affiliated with this order, 14% and 20% with Methanosarcinaceae and 0% and 29% with Methanomicrobiales. Methanomicrobiales dominated in the mesophilic reactors at the given conditions, 69% and 84% of the sequences recovered from direct MeA primed cloning affiliated with this order, 31% and 0% with Methanosarcinaceae and 0% and 16% with Methanobacteriales. No sequence affiliating with Methanosaetaceae was found. MeA primed PCR-single-strand conformation polymorphism indicated that population fluctuations occurred. According to sequence analysis of excised bands, Methanosarcinaceae dominated and Methanobacteriales were significantly represented in the thermophilic fermenter. Only 1 Methanosaetaceae sequence was found. Hydrogenotrophs appear to have a much higher and obligate acetoclastic methanogens a much lower importance than previously thought in biogas production from renewable resources.