| An investigation of biohydrogen production from glucose by Clostridium beijerinckii was conducted in a synthetic wastewater solution. A study examining the effect of initial pH (range 5.7 to 6.5) and COD loading (range 1 to 3 g/L) on the specific conversion and hydrogen production rate has shown interaction behaviour between the two independent variables. Highest conversion of 10.3 mL H2/(g COD/L) was achieved at pH of 6.1 and COD of 3 g/L, whereas the highest production rate of 71 mL H 2/(h*L) was measured at pH 6.3 and substrate loading of 2.5 g COD/L. In general, there appears to be a strong trend of increasing hydrogen production rate with an increase in both substrate concentration and pH. Butyrate (14% to 63%), formate (10% to 45%) and ethanol (16% to 40%) were the main soluble products with other volatile fatty acids and alcohols present in smaller quantities. Absence of the key nutrients biotin, MgSO4.7H2O and FeSO4.7H2O caused a significant decrease in hydrogen yield when compared to the results obtained under standard synthetic wastewater conditions, though no significant difference was observed when concentrations of biotin, MgSO4.7H2O, K2HPO4, KH2PO4, were decreased partially. Preliminary experiments with wastewater effluent obtained from a yogurt manufacturer gave poor biohydrogen production. |
