Cellulase production by Sinorhizobium meliloti strain 224 using waste tobacco as substrate Utilization of waste tobacco for cellulase production

This study has investigated the valorization of waste tobacco, as lignocellulosic biomass, for cellulase production by rhizobium belonging to genus Sinorhizobium. For the first time, Sinorhizobium meliloti strain 224 was used to produce cellulase (Avicelase and carboxymethyl cellulase) during the submerged and solid-state fermentation using tobacco waste as substrate. The effect of substrate chemical modification on enzymes production has been examined as well. The obtained optimal conditions for the maximum activity of both produced enzymes during submerged fermentation using response surface methodology were: 5 g/L of unmodified waste tobacco concentration, incubation time of 2 days and inoculum concentration of 9%. On the other hand, the use of 1 g of sodium hydroxide modified tobacco for the production of cellulase during solid-state fermentation with 10% inoculum, after 2 days of incubation at 28 degrees C, expressed the maximum Avicelase activity of 1.503 U/g and carboxymethyl cellulase activity of 1.615 U/g. In addition to its basic role in plant root colonization and the provision of nitrogen compounds, strain 224 can also be exploited to produce cellulases by bioconversion of plant waste.