EFFECTS OF PHYSICAL PRETREATMENT (CRUSHING AND BALL MILLING) ON SUGARCANE BAGASSE FOR BIOETHANOL PRODUCTION

In order to obtain ethanol, the C-4 plant stem (Sugarcane bagasse) was physically pretreated by crushing (with sieving) and ball milling prior to the enzymatic hydrolysis by Trichoderma viride and fermentation by Saccharomyces cerevisiae. Experiments on the comparison of crushed bagasse samples of different mesh size (20-40, 40-60, 60-80, above 80 mesh) with ball milled samples (5, 10, 15, 20 min) of 20-40 mesh, experiments revealed that ball milled for 20 min had shown better result than crushed sample (above 80 mesh) due to more surface area and greater accessibility to hydrolytic enzymes. It was found that at 48 hrs theoretical yield of glucan and xylan for crush (above 80 mesh size) bagasse sample were 9.23, 40.89% and for 20 min ball milled bagasse sample were 68.17 and 54.19%, respectively. Optimum condition for ethanol fermentation was identified by using hydrolysate of 10% substrate (above 80 mesh size sugarcane bagasse) and 8.85% ethanol was obtained after 24 hrs.