title: Production of polyhydroxyalkanoates from methanol by a new methylotrophic bacterium Methylobacterium sp. GW2.
abstract: A new bacterial strain, isolated from groundwater contaminated with explosives, was characterized as a pink-pigmented facultative methylotroph, affiliated to the genus Methylobacterium. The bacterial isolate designated as strain GW2 was found capable of producing the homopolymer poly-3-hydroxybutyrate (PHB) from various carbon sources such as methanol, ethanol, and succinate. Methanol acted as the best substrate for the production of PHB reaching 40 % w/w dry biomass. PHB accumulation was observed to be a growth-associated process, so that there was no need for two-step fermentation. Optimal growth occurred at 0.5 % (v/v) methanol concentration, and growth was strongly inhibited at alpha concentration above 2 % (v/v). Methylobacterium sp. strain GW2 was also able to accumulate the copolyester poly-3-hydroxybutyrate-poly-3-hydroxyvalerate (PHB/HV) when valeric acid was supplied as an auxiliary carbon source to methanol. After 66 h, a copolymer content of 30 % (w/w) was achieved with a PHB to PHV ratio of 1:2. Biopolymers produced by strain GW2 had an average molecular weight ranging from 229,350 to 233,050 Da for homopolymer PHB and from 362,430 to 411,300 Da for the copolymer PHB/HV.
authors.affiliation: Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec, H4P 2R2, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Yezza
authors.forename: D
authors.initials: D
authors.lastname: Fournier
authors.forename: A
authors.initials: A
authors.lastname: Halasz
authors.forename: J
authors.initials: J
authors.lastname: Hawari
mesh_terms: D001704:Biopolymers / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D020459:Genes, rRNA; D006885:Hydroxybutyrates / Q000378:metabolism*; D007220:Industrial Waste; D000432:Methanol / Q000378:metabolism*; D020580:Methylobacterium / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010421:Pentanoic Acids / Q000378:metabolism; D010802:Phylogeny; D011091:Polyesters / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D019802:Succinic Acid / Q000378:metabolism; D014871:Water Microbiology; D000094122:Polyhydroxybutyrates
chemical_list: D001704:Biopolymers; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D000431:Ethanol; D006885:Hydroxybutyrates; D007220:Industrial Waste; D000432:Methanol; D010421:Pentanoic Acids; D011091:Polyesters; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019802:Succinic Acid; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C003182:poly-beta-hydroxybutyrate; C038780:n-pentanoic acid