title: Biological conversion of methane to liquid fuels: status and opportunities.
abstract: Methane is the main component of natural gas and biogas. As an abundant energy source, methane is crucial not only to meet current energy needs but also to achieve a sustainable energy future. Conversion of methane to liquid fuels provides energy-dense products and therefore reduces costs for storage, transportation, and distribution. Compared to thermochemical processes, biological conversion has advantages such as high conversion efficiency and using environmentally friendly processes. This paper is a comprehensive review of studies on three promising groups of microorganisms (methanotrophs, ammonia-oxidizing bacteria, and acetogens) that hold potential in converting methane to liquid fuels; their habitats, biochemical conversion mechanisms, performance in liquid fuels production, and genetic modification to enhance the conversion are also discussed. To date, methane-to-methanol conversion efficiencies (moles of methanol produced per mole methane consumed) of up to 80% have been reported. A number of issues that impede scale-up of this technology, such as mass transfer limitations of methane, inhibitory effects of H2S in biogas, usage of expensive chemicals as electron donors, and lack of native strains capable of converting methane to liquid fuels other than methanol, are discussed. Future perspectives and strategies in addressing these challenges are also discussed.
authors.affiliation: Department of Food, Agricultural, and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA.
authors.forename: Xumeng
authors.initials: X
authors.lastname: Ge
authors.affiliation: Department of Food, Agricultural, and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA.
authors.forename: Liangcheng
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Food, Agricultural, and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA.
authors.forename: Johnathon P
authors.initials: JP
authors.lastname: Sheets
authors.affiliation: Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Zhongtang
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of Food, Agricultural, and Biological Engineering, The Ohio State University/Ohio Agricultural Research and Development Center, 1680 Madison Ave, Wooster, OH 44691, USA. Electronic address: li.851@osu.edu.
authors.forename: Yebo
authors.initials: Y
authors.lastname: Li
mesh_terms: D056804:Biofuels; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D008697:Methane / Q000737:chemistry*; D020560:Proteobacteria / Q000378:metabolism
chemical_list: D056804:Biofuels; D008697:Methane
keywords: Biogas; Biological conversion; Liquid fuels; Methane; Natural gas