abstract
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Blasting extrusion pretreatment (BEP) was evaluated for obtaining sugar enriched saccharified extracts from sweet sorghum bagasse (SSB) for ethanol fermentation. A factorial design was used for studying the effect of last barrel zone temperature (T
LBZ ) and screw configuration (SC) on carbohydrate release and extraction yield. The experiment with a higher total carbohydrate release was selected (BEP + ES) for a posterior 72 h fermentation and compared against enzymatic saccharified (ES) SSB without using BEP. Fermentation was performed at 28 °C, pH 5.0 and 10% of solids loading (BEP + ES and ES) using the stress tolerant yeast Pichia kudriavzevii ATCC 203,081 for ethanol production. In BEP experiments, screw configuration with one polygon element and a shear zone consisting of 7 reverse elements operating at a TLBZ of 190 °C resulted in the highest carbohydrate release after enzymatic saccharification, achieving a 3-fold increase compared to control. BEP enhanced carbohydrate availability and lignocellulosic biomass degradation activity (enzymatic saccharification and P. kudravzevii fermentation). Ethanol production usining P. kudriavzevii with BEP + ES was 8.65-fold higher than the ES control after 72-h fermentation. Higher initial total carbohydrate (3-fold) and fermentable amino nitrogen (FAN) in BEP + ES (12.41-fold higher) improved SSB fermentability and thus ethanol yield. Glucose was fully consumed in the BEP + ES fermentation, while 91.62% was consumed in the ES experiment. Xylose and mannose/arabinose consumption varied by treatment, but P. kudriavzevvi displayed the ability to co-utilize pentoses and hexoses during fermentation. Compared to previous traditional twin-screw extrusion and ES, BEP enhanced SSB carbohydrate release during enzymatic saccharification, and carbohydrate consumption and ethanol production during fermentation. © The Author(s) 2025.