title: Assessing the influence of CH4 concentration during culture enrichment on the biodegradation kinetics and population structure.
abstract: Methanotrophic communities were enriched in three stirred tank reactors continuously supplied with CH4-laden air at 20, 2 and 0.2 gCH4 m(-3) in order to evaluate the influence of CH4 concentration on the biodegradation kinetics, population structure and potential polyhydroxyalkanoate production under sequential nitrogen limitations. The population structure of the enriched cultures, dominated by type I methanotrophs, was influenced by CH4 concentration. No significant correlation between CH4 concentration and the maximum specific degradation rate (qmax) or the half-saturation constant (KS) was recorded, microorganisms enriched at 2 gCH4 m(-3) presenting the highest qmax and those enriched at 20 and 0.2 gCH4 m(-3) exhibiting the lowest KS. Maximum polyhydroxybutyrate (PHB) contents of 1.0% and 12.6% (w/w) were achieved at 20 and 2 g CH4 m(-3), respectively. Polyhydroxyvalerate (PHV) was also detected at PHV:PHB ratios of up to 12:1 and 4:1 in the communities enriched at 20 and 0.2 gCH4 m(-3), respectively.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain.
authors.forename: Juan C
authors.initials: JC
authors.lastname: López
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Quijano
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain.
authors.forename: Rebeca
authors.initials: R
authors.lastname: Pérez
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina, s/n, 47011, Valladolid, Spain. Electronic address: mutora@iq.uva.es.
authors.forename: Raúl
authors.initials: R
authors.lastname: Muñoz
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D006801:Humans; D007700:Kinetics; D008697:Methane / Q000737:chemistry*; D054813:Polyhydroxyalkanoates / Q000737:chemistry; D000091402:Prohibitins
chemical_list: C000717328:PHB protein, human; D054813:Polyhydroxyalkanoates; D000091402:Prohibitins; D008697:Methane
keywords: Biodegradation kinetics; CH(4) concentration; Methanotroph; Microbial population structure; Polyhydroxyalkanoate