Bioethanol Productions with Sweet Potato (Ipomoea batatas Lam.)

Abstract

To investigate the potential of sweet potato for bioethanol production, saccharification with fungi and ethanol fermentation with yeasts were used. The α-amylase activity of Aspergillus flavus, A. flavus ATCC 9643, A. niger, A. niger ATCC 9642, Mucor hiemalis and Rhizopus sp. was 76.65 ± 0.63, 66.72 ± 7.08, 191.27 ± 4.12, 63.85 ± 0.78, 216.61 ± 4.05 and 26.33 ± 6.82 μmole l-1 min-1, respectively; While the starch conversion rate was 5.02 ± 0.04, 10.92 ± 0.46, 5.01 ± 0.27, 4.18 ± 0.05, 14.18 ± 0.27 and 1.72 ± 0.45%, respectively. The ethanol production of Saccharomyces cerevisiae ATCC 4126 with A. flavus, A. flavus ATCC 9643, A. niger, A. niger ATCC 9642 and M. hiemalis saccharification were 0.38±0.02, 0.84 ± 0.05, 0.57 ± 0.24, 0.05 ± 0.01 and 0.03 ± 0.01%, respectively. While the ethanol production of Pichia stipitis ATCC 58785 with the above microbes saccharification were 0.07 ± 0.01, 1.06 ± 0.02, 0.40 ± 0.08, 0.50 ± 0.04 and 0.04 ± 0.01%, respectively. Therefore, bioethanol production of sweet potato with microbial saccharification and yeast fermentation is a potential process in Taiwan.