title: Effect of CH4/O2 ratio on fatty acid profile and polyhydroxybutyrate content in a heterotrophic-methanotrophic consortium.
abstract: Understanding the role of heterotrophic-methanotrophic (H-Meth) communities is important for improvement of methane (CH4) oxidation capacities (MOC) particularly in conjunction with bio-product development in industrial bio-filters. Initially, a H-Meth consortium was established and enriched from marine sediments and characterized by next generation sequencing of the 16s rDNA gene. The enriched consortium was subjected to 10-50% CH4 (i.e., 0.20-1.6 CH4/O2 ratios) to study the effects on MOCs, biomass growth, fatty acid profiles and biopolymer (e.g. polyhydroxybutyrate; PHB) content. Methylocystis, Methylophaga and Pseudoxanthomonas dominated the H-Meth consortium. Culture enrichment of the H-Meth consortium resulted in 15-20-folds higher MOC compared to seed sediments. Increasing CH4 concentration (and decreased O2 levels) yielded higher MOCs, but did not improve total fatty acid contents. PHB contents varied between 2.5% and 8.5% independently of CH4/O2 ratios. The results suggest that H-Meth consortia could potentially be used in industrial bio-filters for production of biopolymer/biofuel precursors from CH4.
authors.affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia.
authors.forename: Obulisamy P
authors.initials: OP
authors.lastname: Karthikeyan
authors.affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia.
authors.forename: Karthigeyan
authors.initials: K
authors.lastname: Chidambarampadmavathy
authors.affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia.
authors.forename: Saravanan
authors.initials: S
authors.lastname: Nadarajan
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Hong Kong.
authors.forename: Patrick K H
authors.initials: PK
authors.lastname: Lee
authors.affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia; Centre for Bio-discovery and Molecular Development of Therapeutics, James Cook University, Townsville 4811, Queensland, Australia. Electronic address: kirsten.heimann@jcu.edu.au.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Heimann
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D004275:DNA, Ribosomal / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry*; D019015:Geologic Sediments / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D006885:Hydroxybutyrates / Q000032:analysis / Q000737:chemistry*; D008697:Methane / Q000032:analysis*; D042083:Methylocystaceae / Q000737:chemistry / Q000254:growth & development* / Q000302:isolation & purification; D059013:Microbial Consortia; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D011091:Polyesters / Q000032:analysis / Q000737:chemistry*; D000094122:Polyhydroxybutyrates
chemical_list: D004275:DNA, Ribosomal; D005227:Fatty Acids; D006885:Hydroxybutyrates; D008697:Methane; D010100:Oxygen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Bioproducts; Fatty acids; Heterotrophs; Methane remediation; Microbial community; Polyhydroxybutyrate