title: Innovation in biological production and upgrading of methane and hydrogen for use as gaseous transport biofuel.
abstract: Biofuels derived from biomass will play a major role in future renewable energy supplies in transport. Gaseous biofuels have superior energy balances, offer greater greenhouse gas emission reductions and produce lower pollutant emissions than liquid biofuels. Biogas derived through fermentation of wet organic substrates will play a major role in future transport systems. Biogas (which is composed of approximately 60% methane/hydrogen and 40% carbon dioxide) requires an upgrading process to reduce the carbon dioxide content to less than 3% before it is used as compressed gas in transport. This paper reviews recent developments in fermentative biogas production and upgrading as a transport fuel. Third generation gaseous biofuels may be generated using marine-based algae via two-stage fermentation, cogenerating hydrogen and methane. Alternative biological upgrading techniques, such as biological methanation and microalgal biogas upgrading, have the potential to simultaneously upgrade biogas, increase gaseous biofuel yield and reduce carbon dioxide emission.
authors.affiliation: MaREI centre, Environmental Research Institute, University College Cork, Cork, Ireland; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Chongqing 400044, China.
authors.forename: Ao
authors.initials: A
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China. Electronic address: juncheng@zju.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
authors.affiliation: MaREI centre, Environmental Research Institute, University College Cork, Cork, Ireland.
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods / Q000639:trends; D005285:Fermentation; D006859:Hydrogen; D008697:Methane; D014186:Transportation
chemical_list: D056804:Biofuels; D006859:Hydrogen; D008697:Methane
keywords: Algae; Anaerobic digestion; Biogas; Biomass waste; Fermentation; Hythane; Methane; Transport biofuel