In the present work, production of hydrogen via dark fermentation has been carried out using the hydrolyzed rice straw and Clostridium pasteurianum (MTCC116). The hydrolysis reaction of 1.0% alkali pretreated rice straw was performed at 70 degrees C and 10% substrate loading via Fe3O4/Alginate nanocomposite (Fe3O4/Alginate NCs) treated thermostable crude cellulase enzyme following the previously established method. It is noticed that under the optimized conditions, at 70 degrees C the Fe3O4/Alginate NCs treated cellulase has produced around 54.18 g/L sugars as the rice straw hydrolyzate. Moreover, the efficiency of the process illustrates that using this hydrolyzate, Clostridium pasteurianum (MTCC116) could produce cumulative hydrogen of 2580 ml/L in 144 h with the maximum production rate of 23.96 ml/L/h in 96 h. In addition, maximum dry bacterial biomass of 1.02 g/L and 1.51 g/L was recorded after 96 h and 144 h, respectively with corresponding initial pH of 6.6 and 3.8, suggesting higher hydrogen production. (C) 2017 Elsevier Ltd. All rights reserved.