Optimization of culture conditions for hydrogen production by Ethanoligenens harbinense B49 using response surface methodology

The design of an optimum and cost-efficient medium for high-level production of hydrogen by Ethanoligenens harbinense B49 was attempted by using response surface methodology (RSM). Based on the Plackett-Burman design, Fe²⁺ and Mg²⁺ were selected as the most critical nutrient salts. Subsequently, the optimum combination of the selected factors and the sole carbon source glucose were investigated by the Box-Behnken design. Results showed that the maximum hydrogen yield of 2.21 mol/mol glucose was predicted when the concentrations of glucose, Fe²⁺ and Mg²⁺ were 14.57 g/L, 177.28 mg/L and 691.98 mg/L, respectively. The results were further verified by triplicate experiments. The batch reactors were operated under an optimized condition of the respective glucose, Fe²⁺ and Mg²⁺ concentration of 14.5 g/L, 180 mg/L and 690 mg/L, the initial pH of 6.0 and experimental temperature of 35 ± 1 ^oC. Without further pH adjustment, the maximum hydrogen yield of 2.20 mol/mol glucose was obtained based on the optimized medium with further verified the practicability of this optimum strategy.