title: Performance of mesophilic biohydrogen-producing cultures at thermophilic conditions.
abstract: In this study, batch tests were conducted to investigate the performance of mesophilic anaerobic digester sludge (ADS) at thermophilic conditions and estimate kinetic parameters for co-substrate fermentation. Starch and cellulose were used as mono-substrate and in combination as co-substrates (1:1 mass ratio) to conduct a comparative assessment between mesophilic (37 °C) and thermophilic (60 °C) biohydrogen production. Unacclimatized mesophilic ADS responded well to the temperature change. The highest hydrogen yield of 1.13 mol H2/mol hexose was observed in starch-only batches at thermophilic conditions. The thermophilic cellulose-only yield (0.42 mol H2/mol hexose) was three times the mesophilic yield (0.13 mol H2/mol hexose). Interestingly, co-fermentation of starch-cellulose at mesophilic conditions enhanced the hydrogen yield by 26% with respect to estimated mono-substrate yields, while under thermophilic conditions no enhancement in the overall yield was observed. Interestingly, the estimated overall Monod kinetic parameters showed higher rates at mesophilic than thermophilic conditions.
authors.affiliation: Department of Chemical and Biochemical Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Medhavi
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Department of Chemical and Biochemical Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Maritza
authors.initials: M
authors.lastname: Gomez-Flores
authors.affiliation: Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Noha
authors.initials: N
authors.lastname: Nasr
authors.affiliation: Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Elsayed
authors.initials: E
authors.lastname: Elbeshbishy
authors.affiliation: Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada; GreenField Ethanol Inc., Chatham, Ontario N7M 5J4, Canada.
authors.forename: Hisham
authors.initials: H
authors.lastname: Hafez
authors.affiliation: Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Hesham El Naggar
authors.affiliation: Department of Chemical and Biochemical Engineering, Western University, London, Ontario N6A 5B9, Canada; Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada. Electronic address: gnakhla@eng.uwo.ca.
authors.forename: George
authors.initials: G
authors.lastname: Nakhla
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology*; D050260:Carbohydrate Metabolism / Q000502:physiology*; D018920:Coculture Techniques / Q000379:methods; D003198:Computer Simulation; D006859:Hydrogen / Q000302:isolation & purification / Q000378:metabolism*; D008954:Models, Biological; D013213:Starch / Q000378:metabolism*; D013696:Temperature
chemical_list: D056804:Biofuels; D006859:Hydrogen; D013213:Starch
keywords: Co-fermentation; Hydrogen; Mesophilic; Thermophilic; Unacclimatized