title: Biotechnological intensification of biogas production.
abstract: The importance of syntrophic relationships among microorganisms participating in biogas formation has been emphasized, and the regulatory role of in situ hydrogen production has been recognized. It was assumed that the availability of hydrogen may be a limiting factor for hydrogenotrophic methanogens. This hypothesis was tested under laboratory and field conditions by adding a mesophilic (Enterobacter cloacae) or thermophilic hydrogen-producing (Caldicellulosyruptor saccharolyticus) strain to natural biogas-producing consortia. The substrates were waste water sludge, dried plant biomass from Jerusalem artichoke, and pig manure. In all cases, a significant intensification of biogas production was observed. The composition of the generated biogas did not noticeably change. In addition to being a good hydrogen producer, C. saccharolyticus has cellulolytic activity; hence, it is particularly suitable when cellulose-containing biomass is fermented. The process was tested in a 5-m(3) thermophilic biogas digester using pig manure slurry as a substrate. Biogas formation increased at least 160-170% upon addition of the hydrogen-producing bacteria as compared to the biogas production of the spontaneously formed microbial consortium. Using the hydrogenase-minus control strain provided evidence that the observed enhancement was due to interspecies hydrogen transfer. The on-going presence of C. saccharolyticus was demonstrated after several months of semicontinuous operation.
authors.affiliation: Department of Biotechnology, University of Szeged, Temesvári krt. 62, 6726 Szeged, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Bagi
authors.forename: Norbert
authors.initials: N
authors.lastname: Acs
authors.forename: Balázs
authors.initials: B
authors.lastname: Bálint
authors.forename: Lenke
authors.initials: L
authors.lastname: Horváth
authors.forename: Krisztina
authors.initials: K
authors.lastname: Dobó
authors.forename: Katalin R
authors.initials: KR
authors.lastname: Perei
authors.forename: Gábor
authors.initials: G
authors.lastname: Rákhely
authors.forename: Kornél L
authors.initials: KL
authors.lastname: Kovács
mesh_terms: D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology; D005160:Facility Design and Construction; D005740:Gases / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D007218:Industrial Microbiology / Q000379:methods; D008697:Methane / Q000378:metabolism
chemical_list: D005740:Gases; D006859:Hydrogen; D008697:Methane