Rice Straw from Saccharification to Ethanol Simultaneous Fermentation using Aspergillus neoellipticus and Saccharomyces cerevisiae

Authors

  • Amina M. Mohamed Department of Agricultural Microbiology-Soils, Waters and Environmental Research Institute (SWERI) - Agricultural Research Center (ARC), Giza, Egypt.
  • Mahmoud A. Swelim Microbiology at Department of Botany, Faculty of Science, Benha University, Egypt.
  • Mahmoud M. Amer Microbiology at Department of Botany, Faculty of Science, Benha University, Egypt.
  • Ahmed M. Eldin Department of Agricultural Microbiology - Soils, Waters and Environmental Research Institute (SWERI) - Agricultural Research Center (ARC) Giza, Egypt
  • Khadiga I. El-Gabry Department of Agricultural Microbiology - Soils, Waters and Environmental Research Institute (SWERI) - Agricultural Research Center (ARC) Giza, Egypt

Keywords:

Ethanol, Rice Straw, Cellulase, Saccharification, Fermentation, Aspergillus neoellipticus

Abstract

One fungal isolate Am1 from compost identified as Aspergillus neoellipticus [GenBank accessed no. OM760561] was found to possess cellulytic activity of 5806 U (Fpase) when grown in submerged culture using treated rice straw (RS) as substrate. Under successive optimization steps including pH, nitrogen source type and C:N ratio, cellulytic activity increased by 1.4-fold recording 8237 U utilizing
yeast extract at pH 6 and C:N ratio of 1:0.9. Saccharification process using lyophilized raw cellulases produced by A. neoellipticus was optimized achieving saccharification efficiency of 89% at 50ºC and pH7. In a simultaneous saccharification fermentation process using 2L fermentor, optimized saccharification of RS was first held at an enzyme load of 25 U/ g RS after which Saccharomyces cerevisiae was used to ferment the resulting reducing sugar at a concentration of 10%. Optimized fermentation achieved fermentation efficiency of 99.2% at pH6 after 48 h, at a yield of 0.6g ethanol/g reducing sugar or 37.5 g ethanol/ 100 g RS. 

Published

2022-03-25