Enhanced ethanol production using hydrophobic resin detoxified Pine forest litter hydrolysate and integrated fermentation process development supplementing molasses.

Abstract

Globally escalating ethanol demand necessitates the use of hybrid technologies integrating first- and second-generation biofuel feedstocks for achieving the futuristic targets of gasoline replacement with bioethanol. In present study, an optimized two-step sequential pre-treatment (first dilute alkali, then dilute acid) of Pine forest litter (PFL) was developed. Furthermore, the saccharification of pre-treated PFL was optimized through Response Surface Methodology using Box-Behnken Design, wherein 0.558g/g of reducing sugar was released under the optimized conditions (12.5% w/v of biomass loading, 10 FPU/g of PFL enzyme loading, 0.15% v/v Tween-80 and 48h incubation time). Moreover, during hydrolysate fermentation using Saccharomyces cerevisiae NCIM 3288 strain, 22.51 ± 1.02g/L ethanol was produced. Remarkably, hydrophobic resin (XAD-4) treatment of PFL hydrolysate, significantly removed inhibitors (Furfural, 5-hydroxymethylfurfural and phenolics) and increased ethanol production to 27.38 ± 1.18g/L. Furthermore, during fermentation of molasses supplemented PFL hydrolysate (total initial sugar: 100 ± 3.27g/L), a maximum of 46.02 ± 2.08g/L ethanol was produced with 0.482g/g yield and 1.92g/l/h productivity. These findings indicated that the integration of molasses to lignocellulosic hydrolysate, would be a promising hybrid technology for industrial ethanol production within existing bio-refinery infrastructure.