Dark fermentative hydrogen production from pretreated garden wastes by Escherichia coli

One of the strategies to mitigate the environmental problems associated with the increased accumulation of various forms of wastes is to convert the wastes into useful products. In this study different pretreatment and hydrolysis of garden wastes to produce hydrogen using Escherichia coli was investigated. The maximum hydrogen production of 97 mL of H2/g dry garden wastes was obtained after the fermentation by E. coli of hydrolyzate derived from the combined hydrolysis of garden wastes, i.e., acid followed by enzyme treatment. The yield was a 2.7-fold increase when compared to the untreated garden wastes. The hydrolysis solely by enzymes and acid produced 89 and 74 mL of H2/g dry garden wastes, respectively. In addition, 2% sulfuric acid and 2% Viscozyme L were found to be the optimal conditions to obtain maximum hydrogen production from garden wastes. The overall results demonstrated the utilization of garden wastes for the efficient production of hydrogen after appropriate treatment.