Extrusion with thermostable α-amylase injection as pretreatment method for ethanol production from corn starch

Abstract

Pretreatment technologies have been developed to increase the bioconversion rate of biomass into fermentable sugar. The objective of this research was to investigate extrusion with thermostable α-amylase injection at different melt temperatures 95, 115 and 135°C on functional properties, ethanol content and conversion (%) of corn starch extrudates. Saccharomyces cerevisae (ATCC 24858) was used for ethanol production. In the present study, significant increase in ethanol production was achieved by the injection of thermostable α-amylase during extrusion process at melt temperature 115°C. The data clearly showed that thermostable α-amylase injection gave significantly increased (p<0.05) ethanol content at melt temperature 115°C from fermentation period from 24 to 48 hr. Industrial bio-ethanol production by direct fermentation following extrusion with thermostable α-amylase injection and omitting the saccharification step will be very effective in reducing ethanol production costs in countries like U.S. Therefore, ethanol production from extruded corn starch with thermostable α-amylase injection is a significant finding that could be applied to improve bioconversion rate for ethanol production. © 2013 Myat L, et al.