AN INVESTIGATION ON THE BIOCONVERSION 0F REFUSED RICE GRAINS TO ETHANOL

Abstract

Technology for production of bio-ethanol has been developed during the last two decades to the point at which large-scale production will be a reality in the next few years. This is to produce source of energy from some agricultural waste origin. The various raw materials used in the manufacture of ethanol via fermentation are conveniently classified into three main types of raw materials: sugars, starches and cellulosic materials. The objective of the present research is aimed at producing bio-ethanol by hydrolysis of refuse broken rice grains. Four procedures were attempted, of which the last one was the best and the maximum concentration reached of ethanol was 58.5 %. The broken rice grains were washed, dried and milled to a very fine product, followed by adjustment of pH with dilute acid, then cooked in a batch pressure cooker in slurry form. The slurry is then treated with several fungi to hydrolyze starch to dextrins, after which the mash is treated with a second fungus to reduce the dextrins to monosaccharides. The product was then fermented by baker’s yeast saccharomyces cerevisiae (SC) into alcohol, the concentration of which was estimated by density determination of the clear filtrate at different time intervals. In order to separate the alcohol fraction, the liquid product can be either distilled or preferably subjected to separation by pervaporation (Pn) using different membranes of our choice which are fabricated in our lab. Dehydration or separation is accomplished by the use of the most suitable membrane with which the desired separation takes place. Furthermore, the by-product left over can be further processed to reduce its water content then sold as animal food.