Frontiers in Bioengineering and Biotechnology (May 2021)

Effects of Enzyme Volumes on Hydrolysis and Fermentation for Ethanol Production From Leftover Cooked Rice

  • Xikai Chen,
  • Xikai Chen,
  • Yujia Zhao,
  • Yujia Zhao,
  • Boyang Chen,
  • Wang Su,
  • Wang Su,
  • Zhengxian Zhang,
  • Zhengxian Zhang,
  • Yanxu Liu,
  • Xiaobin Xu,
  • Xiaobin Xu,
  • Junhong Tang,
  • Pingzhi Hou,
  • Pingzhi Hou,
  • Wei Han,
  • Wei Han,
  • Wei Han

DOI
https://doi.org/10.3389/fbioe.2021.631089
Journal volume & issue
Vol. 9

Abstract

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This study aimed to utilize the enzymatic hydrolysis of leftover cooked rice (LCR) for fermentative ethanol production. Effect of glucoamylase volumes (V1: 5 U/g, V2: 25 U/g, and V3: 50 U/g) on the performance of LCR hydrolysis was also evaluated. It was found that the highest chemical oxygen demand (COD) of 77.5 g/L and reducing sugar (RS) of 34.6 g/L were achieved at V3. The LCR hydrolyzate obtained from enzymatic hydrolysis was then used as feedstock for ethanol fermentation. Higher ethanol production was obtained when RS increased from 18.7 g/L (V1) to 23.2 g/L (V2). However, lower ethanol production was found when RS further increased to 34.6 g/L (V3) probably because too high RS concentration led to the inhibition on the yeast. The maximum ethanol production and yield were 21.1 g/L and 0.3 g ethanol/g LCR, respectively. The LCR could be a promising substrate for fermentative ethanol production for industrial application.

Keywords