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Subject: Biotechnology and Molecular Biology × Author: Bajaj, Anshu × Start date: 2000 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Genetic improvement of Saccharomyces spp. for ethanol production from starch
    (CCSHAU, 2005) Bajaj, Anshu; Chaudhary, Kamla
    A study was undertaken to improve ethanol production from starch by yeast Saccharomyces spp. A total of 10 isolates of yeast were isolated. After secondary screening in submerged culture conditions six isolates were selected for further investigation. Based on Maximum (6.4U) amylase and ethanol (8.8g/l) production, the Saccharomyces spp. B6 was selected and mutagenized using UV rays and nitrous acid. The Saccharomyces spp. mutant B6U3 produced maximum amylase (8.9U) & ethanol 16.4g/l (in starch) and 26.8g/l (in dextrose) among various mutants and was selected for further studies. The optimization of culture conditions showed that Saccharomyces spp. B6U3 produced increased level of amylase as compared to parent strain. Ethanol production was found to increase with increase in the level of starch. At high concentration of starch the ethanol production was decreased. Starch at a concentration of 10% was found be the best for production of ethanol by Saccharomyces spp. B6U3. Peptone was found to be best nitrogen source for production of ethanol by Saccharomyces Spp. B6U3 producing a maximum 33.4 g/l of ethanol in 48h. In media containing ammonium sulphate, ammonium nitrate casein & urea less amount of ethanol was produced. Peptone was found to the best nitrogen source at 2% level and 34.4g/l of ethanol was produced in 48h of fermentation. Increase in the conc. of peptone led to decreased ethanol production. On increasing the inoculum size upto 20% the ethanol production also increased from 5.6g/l to 32.8g/l after 48h of fermentation. A little variation was found on using 20% of starch grown and dextrose grown inoculum. There was a slight increase in the ethanol production on using dextrose grown inoculum (34.8g/l) than starch grown (33.2g/l) after 48h of fermentation. Ethanol production was found to be maximum after 48h of fermentation. Out of different starch sources used Soluble starch, Sorghum, spoiled wheat, Potato and Cassava, soluble starch was found to be the best substrate for production of ethanol by Sacchromyces spp. B6U3.