Enzymatic hydrolysis of steam-exploded sugarcane bagasse using high total solids and low enzyme loadings

•Hydrolysis of pretreated cane bagasse was performed at high total solids.•Cellic CTec2 was very efficient at high total solids and low enzyme loadings.•The enzymatic hydrolysis results were nicely fit by a quadratic model.•The best conditions resulted in the release of 76.8 g L−1 of glucose equivalents.•C6 fermentation of substrate hydrolysates could increase ethanol production by 39%.

Hydrolysis of phosphoric acid-impregnated steam-treated sugarcane bagasse was pre-optimized using a face-centered central composite design in which the process variables were the substrate total solids (TS, %), agitation intensity (AI, rpm) and enzyme loading (EL, g g−1). Pretreatment was carried out at 180 °C for 10 min using cane bagasse with 50 wt% moisture content containing 9.5 mg of H3PO4 per gram of dry biomass. Hydrolyses were performed for 96 h at 50 °C using Cellic CTec2® and water-washed steam-treated substrates. The highest amount of fermentable sugars was obtained with 20 wt% TS, producing 76.8 g L−1 of glucose equivalents, which corresponded to a total glucan conversion of 69.2 wt% and to a theoretical net increase of 39% in ethanol production from the same sugarcane tonnage without considering the use of leaves, tops and the additional yields from C5 sugars.

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