Bioethanol Production Using Saccharomyces cerevisiae with Different Perspectives: Substrates, Growth Variables, Inhibitor Reduction and Immobilization

Abstract

In the transportation sector, the most commonly used biofuel is ‘bioethanol’ to reduce greenhouse gases. Ethanol production at the industrial level is employed by many yeast, bacteria, and fungi. But Saccharomyces Cerevisiae is most employed yeast. Wide range of substrates has been used for ethanol production such as lignocellulose, molasses, sweat sorghum cane extract, starch based substrate and other wastes. Lignocellulosic hydrolysates contain many inhibitors that can be reduced by treatment with activated charcoal and reducing agents, repeated sequential fermentation, over-liming, evaporation, anion exchanger, enzymatic treatment using peroxidase and laccase, and in-situ detoxification with fermenting microbes. Co-culturing of S. Cerevisiae with other microbes is targeted for optimization of ethanol production, short fermentation time, and for reduced process cost. Yeast cell immobilization has been considered as a potential alternative to enhance ethanol productivity. This paper also reviews the effects of various factors on yeast fermentation for ethanol optimization.