High potential of Rhizopus treated rice bran waste for the nutrient-free anaerobic fermentative biohydrogen production

Abstract

In this study, Rhizopus oligosporus MTCC 556 (Rhizopus) treated rice bran was utilized for the anaerobic bacterial fermentative hydrogen production. The Enterobacter aerogenes MTCC 2822 with nutrients addition fermented the treated rice bran to give hydrogen yield of 5.4 mmol H₂/g of biomass. A closely similar hydrogen yield of 4.6 mmol H₂/g of biomass was obtained from the treated rice bran under the condition without nutrients addition, suggesting the potential of the fungus treatment to produce hydrogen from nutrient-free fermentation. The pretreated rice bran showed efficient hydrogen production upon anaerobic fermentation without nutrients addition. The Rhizopus pretreated biomass can provide required nutrients for the enhancement of hydrogen yield by anaerobic fermentation. The Rhizopus pretreatment of rice bran enhanced the hydrogen production under nutrient-free conditions which reduced the overall production cost. The findings provide a promising solution to efficiently utilize the rice bran waste for low cost hydrogen production.

Keywords: Anaerobic fermentation; Cellulose; Hemicellulose; Lignin; Pretreatment; Rhizopus; Rice bran.