Potential of Sodium Hydroxide Pre treatment of Prosopis juliflora for Fermentable Sugar Production

Abstract

The present study aimed at investigating the potential of sodium hydroxide (NaOH) as a viable alkaline reagent for lignocellulosic pre treatment considering its various benefits of pre treatment. Prosopis juliflora was pre treated with different NaOH concentrations of 1–3 % for varying treatment times of 15-60 min at temperatures of 100, 120 and 140 °C in an autoclave. Maximum lignin reductions at different temperatures were all obtained at the combinations of highest NaOH concentrations and longest treatment times, which indicated a close relationship between pre treatment severity and lignin reduction. The highest carbohydrate retention of 65.09 per cent was observed in the sample pre treated at 120 °C with 2% NaOH and 60 min. Three pre treatment conditions were selected for subsequent enzymatic hydrolysis with Cellic CTec2® enzyme complex for fermentable sugar production along with untreated biomass as control to study the soaking effect. The biomass pretreated with 2.0 % NaOH for 1 h at 120 °C and loaded with 30% enzyme was determined to be the most effective as it resulted in generation of 583.9 mg sugar/g biomass for a corresponding carbohydrate conversion of 90.86 %.