Bioethanol production from sweet potato by co-immobilization of saccharolytic molds and Saccharomyces cerevisiae

Wen-Shiang Lee, I-Chu Chen, Cheng-Hsiung Chang and Shang-Shyng Yang

Renewable Energy, 2012, vol. 39, issue 1, 216-222

Abstract: To investigate the bioethanol production from sweet potato, the saccharification and fermentation conditions of co-immobilization of saccharolytic molds (Aspergillus oryzae and Monascus purpureus) with Saccharomyces cerevisiae were analyzed. The immobilized yeast cells showed that at 10% glucose YPD (yeast extract peptone dextrose) the maximum fermentation rate was 80.23%. Viability of yeasts cells were 95.70% at a final ethanol concentration of 6%. Immobilization enhanced the ethanol tolerance of yeast cells. In co-immobilization of S. cerevisiae with A. oryzae or M. purpureus, the optimal hardening time of gel beads was between 15 and 60 min. Bioethanol production was 3.05–3.17% (v v−1) and the YE/s (yield of ethanol production/starch consumption) was 0.31–0.37 at pH 4, 30 °C and 150 rpm during 13 days fermentation period. Co-immobilization of S. cerevisiae with a mixed cultures of A. oryzae and M. purpureus at a ratio of 2:1, the bioethanol production was 3.84% (v v−1), and the YE/s was 0.39 for a 11 days incubation. However a ratio of A. oryzae and M. purpureus at 1:2 resulted a bioethanol production rate of 4.08% (v v−1), and a YE/s of 0.41 after 9 days of fermentation.

Keywords: Co-immobilization; Bioethanol; Sweet potato; Aspergillus oryzae; Monascus purpureus; Saccharomyces cerevisiae (search for similar items in EconPapers)
Date: 2012
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Citations: View citations in EconPapers (6)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:39:y:2012:i:1:p:216-222

DOI: 10.1016/j.renene.2011.08.024

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