Fermentative Bioconversion of Non-pretreated Wheat Bran to Hydrogen via Cellulolytic Rossellomorea marisflavi and Role of Calcium Oxide Nanoparticles for Enhancement Gas Productivity

Purpose Application of cellulolytic bacteria for hydrogen production has dual benefits in the removal of wastes and as a source of energy without prior treatment strategies. The main purpose of the current study to investigate the effect of calcium oxide (CaO) nanoparticles on the dark fermentative generation of hydrogen by a pure cellulolytic bacterial strain using wheat bran as a lignocellulosic feedstock. Method In the current study, cellulose-decomposing bacteria Rossellomorea marisflavi strain Asu10 was tested for dark fermentative biohydrogen production using wheat bran as a substrate. The impact of calcium chloride (CaCl 2 ) and CaONPs on biohydrogen production was assessed. Results The results revealed that the optimum conditions for bacterial utilization of wheat bran were at pH 7.0, 20 g/L substrate concentration, and 120 rpm shaking after 48 h. The optimum hydrogen yields obtained were 2.1 and 0.9 mol H 2 /mole reducing sugars in a wheat bran fermentation media supplemented with 20 µg/mL of CaONPs and CaCl 2 ; respectively. The optimum energy conversion efficiency (50.2%) was detected at the same concentration of CaONPs. However, the optimum wheat bran saccharification yield (112.5%) was determined at 10 µg/mL CaONPs. Conclusion The current study suggests the application of cellulolytic isolate R. marisflavi strain Asu10 as a promising tool for the renewable production of biohydrogen from agricultural lignocellulosic substrates without the need for pretreatment, the use of CaONPs as a catalyst to increase bio-H 2 productivity by strain. Graphical Abstract