title: Production of hydrogen, ethanol and volatile fatty acids through co-fermentation of macro- and micro-algae.
abstract: Algae may be fermented to produce hydrogen. However micro-algae (such as Arthrospira platensis) are rich in proteins and have a low carbon/nitrogen (C/N) ratio, which is not ideal for hydrogen fermentation. Co-fermentation with macro-algae (such as Laminaria digitata), which are rich in carbohydrates with a high (C/N) ratio, improves the performance of hydrogen production. Algal biomass, pre-treated with 2.5% dilute H2SO4 at 135°C for 15min, effected a total yield of carbohydrate monomers (CMs) of 0.268g/g volatile solids (VS). The CMs were dominating by glucose and mannitol and most (ca. 95%) were consumed by anaerobic fermentative micro-organisms during subsequent fermentation. An optimal specific hydrogen yield (SHY) of 85.0mL/g VS was obtained at an algal C/N ratio of 26.2 and an algal concentration of 20g VS/L. The overall energy conversion efficiency increased from 31.3% to 54.5% with decreasing algal concentration from 40 to 5 VS g/L.
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; School of Engineering, University College Cork, Cork, Ireland.
authors.forename: Ao
authors.initials: A
authors.lastname: Xia
authors.affiliation: MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland.
authors.forename: Amita
authors.initials: A
authors.lastname: Jacob
authors.affiliation: MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland.
authors.forename: Muhammad Rizwan
authors.initials: MR
authors.lastname: Tabassum
authors.affiliation: MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland; Leibniz Institute for Agricultural Engineering, Potsdam, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland. Electronic address: jerry.murphy@ucc.ie.
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D056804:Biofuels; D018533:Biomass; D002241:Carbohydrates / Q000737:chemistry; D002244:Carbon / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000096:biosynthesis* / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D007795:Laminaria / Q000378:metabolism*; D008353:Mannitol / Q000378:metabolism; D058086:Microalgae / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012624:Seaweed / Q000378:metabolism
chemical_list: D056804:Biofuels; D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D000431:Ethanol; D008353:Mannitol; D002244:Carbon; D006859:Hydrogen; D005947:Glucose; D009584:Nitrogen
keywords: Algae; Ethanol; Fermentation; Hydrogen; Volatile fatty acids