Whole Wheat Stillage as an Attractive Feedstock for Ethanol 2nd Generation Biofuel - Effect of Pretreatment on Chemical Composition

The influence of the acidic hydrolysis (reaction time (15 and 30 min.) and acid concentration (1, 3 and 5% H2SO4)) conducted at 121 degrees C on chemical composition of the raw wheat stillage fractions has been studied. After hydrolysis, an attempt was made to detoxify, i.e. to remove substances (mainly furfurals) that inhibit the course of ethanol fermentation. At 30 min. the effect of H2SO4 concentration on the obtained detoxification results was small. In turn, with 15 min., the use of H2SO4 with different concentrations had an effect on detoxification. In the case of furfural (FA), the most favorable result was obtained using 1% H2SO4, while for hydroxymethyl-furfural (HMF) - 5% H2SO4, the degree of FA detoxification reached 96% and HMF 88%. Removal of FA and HMF from the acidic hydrolysis fractions adversely affected the content of monosaccharides. The exception were the experiments in which 1% H2SO4 and the reaction time 30 min was used to hydrolyze the raw wheat stillage.