Increase in Bioethanol Production by Random UV Mutagenesis of S.cerevisiae and by Addition of Zinc Ions in the Alcohol Production Media

Bioethanol is regarded as one of most demanding fuel as an alternative to fossil fuel as it is renewable and environment friendly. In industry, bioehanol is produced usually by using molasses as the carbon source with the help of S.cerevisiae. But due to steep hike in the prices of molasses, the production cost of biotehanol is on constant rise. Therefore, there is urgent need to evolve alternative strategy which can lower down the production cost of bioehanol.This study is directed towards finding out some rationale approaches which can increase the production rate of biotehanol, thereby decreasing the production cost.We have applied random mutagenesis approach by UV exposure for strain improvement of existing strain which is not alcohol tolerant. 25 minutes UV exposure to existing strain produced a mutant strain which produced 12% (v/v) alcohol in fermentor whereas WT S. cerevisiae produced only 8% (v/v).We have also attempted to register increase in alcohol production by adding of Zinc ion in alcohol producing media. It was standardized that 20 mM Zinc sulphate addition to YEPD broth resulted in maximum increase in alcohol production in shake flask.When 20 mM Zinc sulphate was added to fermentation broth in 2 litre laboratory based fermentor, it resulted in 13.2% (v/v) alcohol production as compared to 8% (v/v) alcohol production by WT strain. There was also 3.2 fold increases in alcohol dehydrogenase activity when it was measured in presence of 20 mM zinc sulphate as compared to control (ADH activity measured using same cell lysate in the absence of zinc sulphate).