Thermo-Mechanical Extrusion and Sodium Hydroxide Pretreatments for Ethanol Production from Destarched Corn Fiber

摘要

The effect of thermo-mechanical extrusion and sodium hydroxide pretreatments on ethanol production from destarched corn fiber (DCF) was investigated. DCF was extruded at screw speed of 300 rpm, feed moisture content of 30%, and melt temperature of 140℃ and then pretreated by 0.75, 1.50, 2.25, and 3.00% of sodium hydroxide solution in the autoclave at 121℃ for 1 h. After sodium hydroxide pre-treatment, the liquid and solid fractions were separated by centrifugation. The dry solid fraction was used for the determination of composition, characterization (crystallinity index, microstructure, degree of polymerization), enzymatic saccharification and fermentation process. Extruded DCF pretreated by 0.75% sodium hydroxide significantly decreased lignin content, crystallinity index and degree of polymerization for efficient enzymatic saccharification and gave significant increase in ethanol yield (35.13 g L~(-1)). Therefore, thermo-mechanical extrusion followed by 0.75% of sodium hydroxide pretreatment was a good pretreatment for ethanol production from DCF.