Hydrogen production from continuous fermentation of xylose during growth of Clostridium sp. strain No. 2

Abstract

Experimental conditions are presented for continuous fermentation of xylose and glucose to hydrogen (H₂), using Clostridium sp. strain No. 2 growing in 300 mL of culture containing 0.3% substrate, either without pH control or with the pH controlled at 6.0. The H₂ production rate increased in proportion to increasing dilution rate within the range of about 0.4 to 1.0 h⁻¹. The maximal H₂ production rates of 21.03 and 20.40 mmol∙h⁻¹∙L⁻¹ were obtained from xylose and glucose with dilution rates of 0.96 and 1.16 h⁻¹, respectively, at pH 6.0. About 2.06 mol H₂ with a dilution rate of 0.21 h⁻¹ at pH 6.0 and 2.36 mol H₂ with a dilution rate of 0.18 h⁻¹ were formed per mole of xylose and glucose consumed, respectively, at uncontrolled pH.Key words: hydrogen production, continuous fermentation, xylose, Clostridium sp. strain no. 2.