Bio-ethanol Production from Spent Grain and its Various Applications: An Overview

The challenge to find and develop alternative sources of energy so that our decreasing reserves of crude oil and other fossil fuels may be conserved is of concern. However, this energy source must not interfere nor compete with human means of survival. The brewery industries generate a large amount of waste with a spent grain (SG) being the major one, which is currently under-utilized and usually disposed off indiscriminately. This has raised environmental concern. However, spent grain is a rich source of lignocellulose, which can be converted through hydrolysis and fermentation to bio-ethanol and this can be used as pure or blended fuel for automobile and heating purposes. The aim of this article is to review the composition, applications and other uses of brewer’s spent grain (SG). The full utilization of existing technology and the promise of new development were also examined in this review. Also reviewed were works of few researchers who had worked on brewer’s spent grain. This study concluded that spent grain though a waste product can be used to generate energy in form of ethanol production and that the quantity of ethanol that can be produced from spent grains depends on the quantity of reducing sugar and residual starch content. The higher the reducing sugar and residual starch content the higher the quantity of ethanol that can be extracted. Thus, spent grain is a potential biomass for the production of bio-fuel particularly in developing nations.