Combination of high solid load, on‐site enzyme cocktails and surfactant in the hydrolysis of hydrothermally pretreated sugarcane bagasse and ethanol production.

Abstract

In this study, the combined strategy of using high solid load, on-site enzyme cocktails and surfactant was evaluated in sac- charifcations of hydrothermally pretreated sugarcane bagasse (HP-SB) and ethanol production. The hydrolyses were carried

in fed-batch mode with a solid load of 10–40% (w/v) at time intervals of 12 h, using two homemade enzyme extracts (ES1 from Aspergillus niger monoculture and ES2 from A. niger, Trametes versicolor and Pleurotus ostreatus consortium), 10 FPU/gds of cellulase loading at 50 °C for 72 h. After optimization of solid loading, new saccharifcations were performed

with the addition of 5% (w/v) surfactant (Triton X-100). The HP of SB led to a signifcant reduction of 69.26% in hemicel- luloses content, but also preserved the cellulose fraction in HP-SB. The increase of HP-SB load in hydrolysis from 10 to

35% signifcantly improved the release of total reducing sugars (TRS), with an increase of 188.54% in ES1 and 177.46% in ES2. The use of Triton X-100 in saccharifcations of HP-SB (30% w/v) also positively contributed to TRS production, with an increase in TRS of 6.22% in ES1S and 24% in ES2S. The fermentation of the hydrolysate after surfactant-assisted hydrolysis of HP-SB (30% w/v) led to an ethanol yield of 81.70% for F1S and 88.03% for F2S. Results demonstrated that the integrated use of high solid load, low-cost on-site enzyme cocktail and surfactant (Triton X-100) can be a promising approach to improve the efciency of bioconversion of lignocellulosic biomass to fermentable sugars.