An analysis of feasibility of bioethanol production from Taiwan sorghum liquor waste

In order to evaluate the feasibility of using sorghum liquor waste for bioethanol production, we serially investigated the effectiveness of physical treatment, microwave irradiation pretreatment, enzymatic hydrolysis, and fermentation. Composition analysis revealed that Kinmen sorghum liquor waste (KS) and Chiayi sorghum liquor waste (CS) contain approximately 17.2 ± 0.7% and 18.2 ± 0.6% cellulose, 19.0 ± 0.6% and 21.6 ± 1.0% hemicellulose, 18.5 ± 0.8% and 20.6 ± 1.7% acid detergent lignin, and 22.1 ± 0.7% and 23.3 ± 0.4% starch, respectively, on dry weight basis. The reducing sugar yield obtained after microwave irradiation pretreatment and enzymatic hydrolysis of KS and CS were 331.1 and 341.3 mg/g dry weight. The ethanol yields obtained after fermentation of KS and CS hydrolysates with Saccharomyces cerevisiae were 0.13 and 0.14 g/g dry weight, respectively. This operation of pretreatment may provide a suggestible pattern of utilizing feedstock that contain lignocellulose and starchy for ethanolic fermentation.