Hydrogen and Ethanol production from Glycerol-containing wastes discharged after biodiesel manufacturing process

Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Japan.
Journal of Bioscience and Bioengineering (Impact Factor: 1.88). 10/2005; 100(3):260-5. DOI: 10.1263/jbb.100.260
Source: PubMed


H2 and ethanol production from glycerol-containing wastes discharged after a manufacturing process for biodiesel fuel (biodiesel wastes) using Enterobacter aerogenes HU-101 was evaluated. The biodiesel wastes should be diluted with a synthetic medium to increase the rate of glycerol utilization and the addition of yeast extract and tryptone to the synthetic medium accelerated the production of H2 and ethanol. The yields of H2 and ethanol decreased with an increase in the concentrations of biodiesel wastes and commercially available glycerol (pure glycerol). Furthermore, the rates of H2 and ethanol production from biodiesel wastes were much lower than those at the same concentration of pure glycerol, partially due to a high salt content in the wastes. In continuous culture with a packed-bed reactor using self-immobilized cells, the maximum rate of H2 production from pure glycerol was 80 mmol/l/h yielding ethanol at 0.8 mol/mol-glycerol, while that from biodiesel wastes was only 30 mmol/l/h. However, using porous ceramics as a support material to fix cells in the reactor, the maximum H2 production rate from biodiesel wastes reached 63 mmol/l/h obtaining an ethanol yield of 0.85 mol/mol-glycerol.

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    • "Biodiesel is a renewable, healthier, environmentally friendly and sustainable alternative for fossil fuels.[1] The global biodiesel market is estimated to reach 140 billion liters by 2016 and, with increasing annual growth, production would reach 159 billion liters by 2020.[2] Biodiesel is produced by transesterification of feedstock such as vegetable oil and animal fats, causing an increase in the cost of these raw materials.[3] To meet the increasing demand, waste generated from restaurants and the meat processing industry containing CONTACT Satinder Kaur Brar "
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    ABSTRACT: The effect of adding crude glycerine during continuous sewage sludge anaerobic digestion was investigated under thermophilic and mesophilic temperatures. Addition of CGY at thermophilic temperature range showed a negative impact on stability and performance of the process, even at low doses. The extreme pH values of CGY, together with the rapid release of VFA, causes SS alkalinity fail to control pH drop. On the contrary, at mesophilic temperature range the process performs steadily, with 148% increase in methane production when CGY represented 1% v/v of the influent (27% of influent COD). Further CGY percentages did not show any added improvement; the biomass shift, due to a high C/N ratio, could explain this behaviour. Results suggested that CGY can be used as co-substrate of SS anaerobic digestion though, depending on the characteristics of CGY, and on operational conditions, different parameters should be taken into account to achieve a steady and consistent operation. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Oct 2015 · Bioresource Technology
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    • "The theoretical yield for each intermediary stage was calculated as a combination of the theoretical H 2 yields of pure glucose (4 mol H2 mol −1 glucose consumed ) and glycerol (1 mol H2 mol −1 glycerol consumed ), weighted by their respective proportions in the feeding mixture (Ito et al. 2005; Akutsu et al. 2009). DGGE profiles were aligned and analyzed with GelCompar II software (Applied Maths, Sint-Martens-Latem, Belgium), to obtain the matrix of relative band intensity according to band position. "
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