Today, there is a growing interest in biofuel production because of the increasing concerns about hydrocarbon fuels shortage and global climate changes. Biofuels like bioethanol, biodiesel, biogas etc. offer a number of environmental, social and economic advantages. With the increasing need of ethanol for blending with the petrol, lignocellulosic wastes are being looked upon as a source. The corn cob has been washed with water thoroughly to remove the extraneous matter and then dried at 55 °C in an oven till a constant weight has been obtained. The dried biomass has been thoroughly ground and sieved to obtain a particle size of 2-5mm which increase the surface area of the substrate hence increases the yield. Delignification of corn cob has been done with H_2SO_4 under pressure 15psi and temperature 121 °C. All the experiments have been done in duplicates to verify the accuracy of the results. The SEM analysis has been done which shows that cellulose forms a skeleton surrounded by hemicelluloses as a matrix and encrusting lignin. The hydrolysate has been treated with activated charcoal to remove the inhibitors like furfural, HMP (hydroxy methyl furfural), weak acids (acetic acid, formic acid, levlunic acid), resins, terpens etc. generated during pretreatment of lignocellulosic material. The enzymatic hydrolysis of solid cake has been carried for the saccharification of cellulose into glucose by using three cellulase enzymes-CM-10T, NS-22086, NS-22119 at 50 °C/170 rpm/72 hr. This has been followed by the subsequent analysis of the total reducing sugars and glucose obtained by the DNS colorimetric assay at 540 nm. The total reducing sugars present in the activated charcoal treated and untreated hyrolysate are 30.00 mg/ml and 33.76 mg/ml respectively. Enzymatically treated solid cake contained total reducing sugars (CM-10T) 52.8 mg/ml, (NS-22086) 73.80 mg/ml and (NS-22119) 67.42 mg/ml. The liquid hyrolysate fraction has been analysed for their chemical composition with HPLC, FT-IR. X-RD of solid cake has been done to study "Crystallinity Index" after pretreatment. The hydrolysed sample has been inoculated with 24 hr old culture of Saccharomyces cerevisiae, Pichia stipitis and mixture of both. The sample has been incubated at 28 °C/170 rpm/72 hr and pH maintained 4.5-5.5. Potassium dicromate assay has been done to study ethanol percentage which is 3.141% (v/v).
展开▼
