title: Ammonia tolerant inocula provide a good base for anaerobic digestion of microalgae in third generation biogas process.
abstract: This study investigated the ability of an ammonia-acclimatized inoculum to digest efficiently protein-rich microalgae for continuous 3rd generation biogas production. Moreover, we investigated whether increased C/N ratio could alleviate ammonia toxicity. The biochemical methane potential (BMP) of five different algae (Chlorella vulgaris)/manure (cattle) mixtures showed that the mixture of 80/20 (on VS basis) resulted in the highest BMP value (431mLCH4gVS-1), while the BMP of microalgae alone (100/0) was 415mLCH4gVS-1. Subsequently, anaerobic digestion of those two substrates was tested in continuous stirred tank reactors (CSTR). Despite of the high ammonium levels (3.7-4.2g NH4+-NL-1), CSTR reactors using ammonia tolerant inoculum resulted in relatively high methane yields (i.e. 77.5% and 84% of the maximum expected, respectively). These results demonstrated that ammonia tolerant inocula could be a promising approach to successfully digest protein-rich microalgae and achieve a 3rd generation biogas production.
authors.affiliation: Biotechnological Processes for Energy Production Unit - IMDEA Energy, 28935 Móstoles, Madrid, Spain; Department of Agricultural Microbiology, Faculty of Agriculture, Zagazig University, 44511 Zagazig, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mahdy
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kgs. Lyngby, Denmark. Electronic address: ioanf@env.dtu.dk.
authors.forename: Ioannis A
authors.initials: IA
authors.lastname: Fotidis
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Enrico
authors.initials: E
authors.lastname: Mancini
authors.affiliation: Biotechnological Processes for Energy Production Unit - IMDEA Energy, 28935 Móstoles, Madrid, Spain; Biofuels Unit - Research Center for Energy, Environment and Technology (CIEMAT), 28040 Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ballesteros
authors.affiliation: Biotechnological Processes for Energy Production Unit - IMDEA Energy, 28935 Móstoles, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: González-Fernández
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Irini
authors.initials: I
authors.lastname: Angelidaki
mesh_terms: D000641:Ammonia / Q000737:chemistry / Q000378:metabolism; D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology*; D002417:Cattle; D008372:Manure; D008697:Methane / Q000032:analysis / Q000378:metabolism; D058086:Microalgae / Q000737:chemistry / Q000378:metabolism
chemical_list: D056804:Biofuels; D008372:Manure; D000641:Ammonia; D008697:Methane
keywords: Ammonia inhibition; Anaerobic digestion; BMP; Co-digestion; Microalgae