title: Mini review: hydrogen and ethanol co-production from waste materials via microbial fermentation.
abstract: The simultaneous production of hydrogen and ethanol by microorganisms from waste materials in a bioreactor system would establish cost-effective and time-saving biofuel production. This review aims to present the current status of fermentation processes producing hydrogen accompanied by ethanol as a co-product. We outlined the microbes used and their fundamental pathways for hydrogen and ethanol fermentation. Moreover, we discussed the exploitation of renewable and sustainable waste materials as promising feedstock and the limitations encountered. The low substrate bioconversion rate in hydrogen and ethanol co-production is regarded as the primary constraint towards the development of large scale applications. Thus, microbes with an enhanced capability have been generated via genetic manipulation to diminish the inefficiency of substrate consumption. In this review, other potential approaches to improve the performance of co-production through fermentation were also elaborated. This review will be a useful guide for the future development of hydrogen and ethanol co-production using waste materials.
authors.affiliation: Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Chiu-Shyan
authors.initials: CS
authors.lastname: Soo
authors.affiliation: Faculty of Applied Sciences, UCSI University, 56000, Cheras, Kuala Lumpur, Malaysia.
authors.forename: Wai-Sum
authors.initials: WS
authors.lastname: Yap
authors.affiliation: KDU University College, Damansara Jaya, 47400, Petaling Jaya, Selangor, Malaysia.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Hon
authors.affiliation: Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia. phanglaiyee@upm.edu.my.
authors.forename: Lai-Yee
authors.initials: LY
authors.lastname: Phang
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods; D053858:Metabolic Networks and Pathways; D012037:Refuse Disposal / Q000379:methods*
chemical_list: D000431:Ethanol; D006859:Hydrogen
keywords: Co-production; Ethanol; Hydrogen; Microbial fermentation; Waste