title: Archaea diversity within a commercial biogas plant utilizing herbal biomass determined by 16S rDNA and mcrA analysis.
abstract: OBJECTIVE
  The Archaea diversity was evaluated in an agricultural biogas plant supplied with cattle liquid manure and maize silage under mesophilic conditions.
  
  
  RESULTS
  Two different genes (16S rRNA; methyl-coenzyme-M-reductase, MCR) targeted by three different PCR primer sets were selected and used for the construction of three clone libraries comprising between 104 and 118 clones. The clone libraries were analysed by restriction fragment polymorphism (RFLP). Between 11 and 31 operational taxonomic units (OTUs) were detected and assigned to orders Methanomicrobiales, Methanosarcinales and Methanobacteriales. Over 70% of all Archaea OTUs belong to the order Methanomicrobiales which mostly include hydrogenotrophic methanogens. Acetotrophic methanogens were detected in minor rates. Similar relative values were obtained by a quantitative real-time PCR analysis.
  
  
  CONCLUSIONS
  The results implied that in this biogas plant the most of the methane formation resulted from the conversion of H(2) and CO(2).
  
  
  CONCLUSIONS
  This study reports, for the first time, a molecular analysis of the archaeal community in this type of agricultural biogas plants. Therein the hydrogenotrophic methanogenesis seems to be the major pathway of methane formation. These results are in contrast with the common thesis that in biogas fermentations the primary substrate for methanogenesis is acetate.
authors.affiliation: Leibniz-Institut für Agrartechnik Potsdam-Bornim eV, Abteilung Bioverfahrenstechnik, Potsdam-Bornim, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Nettmann
authors.forename: I
authors.initials: I
authors.lastname: Bergmann
authors.forename: K
authors.initials: K
authors.lastname: Mundt
authors.forename: B
authors.initials: B
authors.lastname: Linke
authors.forename: M
authors.initials: M
authors.lastname: Klocke
mesh_terms: D000818:Animals; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D019149:Bioreactors; D002417:Cattle; D017931:DNA Primers; D019641:DNA, Archaeal / Q000032:analysis / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D015723:Gene Library; D008372:Manure / Q000382:microbiology*; D010088:Oxidoreductases / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D003313:Zea mays
chemical_list: D017931:DNA Primers; D019641:DNA, Archaeal; D004275:DNA, Ribosomal; D008372:Manure; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C021572:methyl coenzyme M reductase