Direction of glucose fermentation towards hydrogen or ethanol production through on-line pH control
✍ Scribed by Dogan Karadag; Jaakko A. Puhakka
- Book ID
- 103832657
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 688 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
The present study investigated the production of hydrogen (H 2 ) and ethanol from glucose in an Anaerobic Continuous Stirred Tank Reactor (ACSTR). Effects of hydraulic retention time (HRT) and pH on the preference of producing H 2 and/or ethanol and other soluble metabolic products in an open anaerobic enriched culture were studied. Production rates of H 2 and ethanol increased with the increase of biomass concentration. Open anaerobic fermentation was directed and managed through on-line pH control for the production of H 2 or ethanol. Hydrogen was produced by ethanol and acetate-butyrate type fermentations. pH has strong effect on the H 2 or ethanol production by changing fermentation pathways. ACSTR produced mainly ethanol at over pH 5.5 whereas highest H 2 production was obtained at pH 5.0. pH 4.9 favored the lactate production and accumulation of lactate inhibited the biomass concentration in the reactor and the production of H 2 and ethanol.
The microbial community structure quickly responded to pH changes and the Clostridia dominated in ACSTR during the study. H 2 production was maintained mainly by Clostridium butyricum whereas in the presence of Bacillus coagulans glucose oxidation was directed to lactate production.