title: Optimised biogas production from microalgae through co-digestion with carbon-rich co-substrates.
abstract: Microalgae can be used to upgrade biogas to biomethane and subsequently be digested for biogas production. However, the low C:N ratio of species such as Arthrospira platensis may cause ammonia inhibition and low process stability during anaerobic digestion. This study investigates co-fermentation of A. platensis with carbon-rich co-substrates (barley straw, beet silage and brown seaweed) at a C:N ratio of 25 to enhance biomass conversion. No synergistic effects on biomethane potential could be proven in batch fermentation tests. However continuous digestion trials showed significantly improved process stability. Mono-digestion of A. platensis was stable only at an organic loading of 1.0gVSL(-1)d(-1). The optimum process co-digested A. platensis with seaweed and achieved stable operation at an organic loading of 4.0gVSL(-1)d(-1). Co-digestion of microalgae and seaweed can be effectively applied to integrated coastal biomethane systems.
authors.affiliation: The MaREI Centre, Environmental Research Institute, University College Cork, Ireland; Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Department of Bioengineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: The MaREI Centre, Environmental Research Institute, University College Cork, Ireland.
authors.forename: Navajyoti
authors.initials: N
authors.lastname: Kalita
authors.affiliation: The MaREI Centre, Environmental Research Institute, University College Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Wall
authors.affiliation: The MaREI Centre, Environmental Research Institute, University College 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: The MaREI Centre, Environmental Research Institute, University College 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: D000693:Anaerobiosis; D061249:Batch Cell Culture Techniques; D027461:Beta vulgaris; D056804:Biofuels; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D002244:Carbon / Q000494:pharmacology*; D005232:Fatty Acids, Volatile / Q000096:biosynthesis; D007700:Kinetics; D008697:Methane / Q000378:metabolism; D058086:Microalgae / Q000187:drug effects / Q000378:metabolism*; D009584:Nitrogen / Q000302:isolation & purification; D012820:Silage
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D002244:Carbon; D009584:Nitrogen; D008697:Methane
keywords: Algae; Ammonia inhibition; C:N ratio; Co-digestion; Seaweed