Effect of Gama Irradiation of Bioethanol Producing Microorganisms on Bioethanol Formation from Sugarcane Bagasse and Potato Peels

THE PRESENT work was designed to investigate the production of bioethanol from agriculture feedstock (sugarcane bagasse and potato peels) using Saccharomyces cerevisiae ATCC 7754 and Zymomonas mobilis ATCC 29191, exposed to different doses of gamma irradiation (0, 100, 300, 500, 1000 and 1500 Gy). The effect of different hydrolysis pretreatments of feedstock on resulting sugars (initial sugars), which were later fermented to bioethanol, was also tested and compared to non-hydrolyzed feedstock. Hydrolysis of sugarcane bagasse and potato peels was conducted with dilute sulphuric acid (2 and 6 % v/v), running at 100 and 120˚C for 30 and 60 min of retention time. The highest bioethanol concentration obtained from sugarcane bagasse was 10.3 gL-1, which was produced by Sacch. cerevisiae ATCC 7754 irradiated at 300 Gy from hydrolysate of 2 % (v/v) H2SO4 at 120°C for 60 min treatment. From the same treatment, the highest bioethanol concentration obtained by Z. mobilis ATCC 29191 was 4.4 gL-1, when irradiated at 100 Gy. This acid treatment produced 23.7 gL-1 of sugars from the feedstock. The highest bioethanol concentration obtained from potato peels was 7.5 gL-1, produced by Sacch. cerevisiae ATCC 7754 irradiated at 300 Gy from hydrolysate of 6 % (v/v) H2SO4 at 100°C for 60 min treatment, followed by 5.7 gL-1 produced by Z. mobilis ATCC 29191 irradiated at 100 Gy. This treatment produced 24 gL-1 of sugars from the feedstock