Dark fermentative hydrogen production with crude glycerol from biodiesel industry using indigenous hydrogen-producing bacteria

Glycerol is an inevitable by-product from biodiesel synthesis process and could be a promising feedstock for fermentative hydrogen production. In this study, the feasibility of using crude glycerol from biodiesel industry for biohydrogen production was evaluated using seven isolated hydrogen-producing bacterial strains (Clostridium butyricum, Clostridium pasteurianum, and Klebsiella sp.). Among the strains examined, C. pasteurianum CH4 exhibited the best biohydrogen-producing performance under the optimal conditions of: temperature, 35 degrees C; initial pH, 7.0; agitation rate, 200 rpm; glycerol concentration, 10 g/l. When using pure glycerol as carbon source for continuous hydrogen fermentation, the average H-2 production rate and H-2 yield were 103.1 +/- 8.1 ml/h/l and 0.50 +/- 0.02 mol H-2/mol glycerol, respectively. In contrast, when using crude glycerol as the carbon source, the H-2 production rate and H-2 yield was improved to 166.0 +/- 8.7 ml/h/l and 0.77 +/- 0.05 mol H-2/mol glycerol, respectively. This work demonstrated the high potential of using biodiesel by-product, glycerol, for cost-effective biohydrogen production. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.