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Process optimization of biological hydrogen production from molasses by a newly isolated Clostridium butyricum W5

Paper ID Volume ID Publish Year Pages File Format Full-Text
21420 43221 2009 7 PDF Available
Title
Process optimization of biological hydrogen production from molasses by a newly isolated Clostridium butyricum W5
Abstract

This work sought to optimize fermentation parameters in a batch process for hydrogen production from molasses by a newly isolated Clostridium butyricum W5. Hydrogen yield and production rate, bacterial biomass and volatile fatty acids, including acetic, lactic and butyric acids, were measured. Key fermentation operation parameters, including concentration of carbon and nitrogen sources, growth temperature and pH, and inoculum size were investigated. The best results in terms of hydrogen yield and productivity were obtained under the conditions of 100 g/L molasses, 1.2 g/L NH4NO3, 39 °C at pH 6.5 with initial cell concentration of 9 × 104 cell/ml. Maximum hydrogen yield was 1.85 mol hydrogen/mol hexose, corresponding to a hydrogen production rate of 17.38 mmol/h/L. Experimental data showed that the acetic/butyric acid ratio remained relatively stable with an increase in molasses concentration, while the unfavoured product, lactic acid, portion increased. No solvent (ethanol, butanol and acetone) was detected during the fermentation. Propionic acid was measured at a very low level in the hydrogen fermentation. Statistical analysis showed that hydrogen yield increased exponentially with the increase in cell growth, and that there was no correlation between the hydrogen yield and ratio of acetic acid to butyric acid.

Keywords
Hydrogen production; Fermentation; Molasses; Clostridium butyricum; Volatile fatty acid; Regression analysis
First Page Preview
Process optimization of biological hydrogen production from molasses by a newly isolated Clostridium butyricum W5
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 107, Issue 2, February 2009, Pages 138–144
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering