Biohydrogen Production Through Dark Fermentation by a Microbial Consortium Using Whey Permeate as Substrate

• Published in: Applied biochemistry and biotechnology 2014-04, Vol.172 (7), p.3670-3685
• Main Authors: Romão, B. B, Batista, F. R. X, Ferreira, J. S, Costa, H. C. B, Resende, M. M, Cardoso, V. L
• Format: Article
• Language: English
• Subjects: Ammonium; ammonium sulfate; Anaerobic conditions; Bacteria - metabolism; Biochemistry; Biodiesel fuels; Biohydrogen; Biological and medical sciences; Bioreactors - microbiology; Biotechnology; butyric acid; carbon; Carbon sources; Cheese; Cheese - analysis; cheese whey; Chemistry; Chemistry and Materials Science; Dairy products; Effluent treatment; Ethanol; Fermentation; ferrous sulfate; fossil fuels; Fundamental and applied biological sciences. Psychology; Hydrogen; Hydrogen - metabolism; Hydrogen production; Industrial Microbiology - instrumentation; Industrial Microbiology - methods; iron; lactic acid; lactose; Lactose - metabolism; Metabolites; Methods. Procedures. Technologies; Microbial Consortia; Microbial engineering. Fermentation and microbial culture technology; Organic acids; Substrates; Sulfates; Waste Products - analysis; Wastewater treatment; whey
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-014-0778-5

Nowadays, hydrogen produced globally has been synthesized from fossil fuel with limited source. Therefore, research has been developed in order to explore biological H₂ production by dark fermentation. The purpose of this work was to evaluate the effect of initial pH and ferrous sulfate and ammonium sulfate concentrations on the production of biohydrogen by dark fermentation. The process was carried out in batch mode under anaerobic conditions, in the absence of light, and at standard room temperature and pressure. A microbial consortium provided by the effluent treatment plant of a local dairy company was inoculated into a synthetic medium supplemented with cheese whey permeate (20 g/L of lactose) as a carbon source. The influence of three variables was analyzed by a central composite design 2⁽³⁾, and the optimum results of hydrogen yield (4.13 mol H₂/mol lactose) and productivity (86.31 mmol H₂/L/day) were achieved at initial pH 7.0 and FeSO₄ and (NH₄)₂SO₄ concentrations of 0.6 and 1.5 g/L, respectively. Under these conditions, the kinetic parameters of fermentation were investigated by analyzing the profile of H₂ yield and productivity, metabolite concentrations, pH, and concentration of dissolved iron. In the kinetic analysis, the modified Gompertz equation described adequately the fermentative hydrogen production from cheese whey permeate (R ² = 0.98). The profile of ethanol and volatile organic acids showed that lactic acid and butyric acid were the main metabolites produced, and the sum of both by-products corresponded to about 58 % of the total metabolites.