Ethanol production from alkaline-treated rice straw via Separate Hydrolysis and Fermentation (SHF) using K. marxianus UniMAP 1-1

Abstract

The decreasing reserves of non-renewable energy especially fossil fuel has led to an urgent need to establish alternative fuels. Ethanol is one of the energies explored, which can be generated by fermentation method. The use of environmentally friendly material such as lignocellulosic biomass to develop a biofuel is significant. Ethanol production at high temperature was preferred as it will significantly reduce the cooling cost involved. Thus, the use of thermotolerant strain in the fermentation process was recommended. In this study, separate hydrolysis and fermentation (SHF) was employed to produce ethanol from 2% sodium hydroxide-treated rice straw using cellulase enzyme, and fermented by a thermotolerant K. marxianus UniMAP 1-1 strain. The fermentation process was done at two different temperatures, 37℃ and 50℃, at pH 4.8. The ethanol yield from both 37℃ and 50℃ was 0.36 g/g and 0.38 g/g, respectively. K. marxianus UniMAP 1-1 showed a good production of ethanol at elevated temperature. This is the first study reporting ethanol production from rice straw using K. marxianus UniMAP 1-1. Thus, this study can improve our understanding of the development of thermotolerant yeast accountable to the SHF process for ethanol production.