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Characterization of an ethanol producing yeast isolate and optimization of ethanol fermentation

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dc.contributor.advisor Choudhury, Naiyyum
dc.contributor.advisor Ahmed, Monzur Morshed Quayum, Md. Abdul 2012-03-06T03:28:45Z 2012-03-06T03:28:45Z 2011 2011-11
dc.identifier.other ID 10376003
dc.description This thesis report is submitted in partial fulfillment of the requirement for the degree of Masters of Science in Biotechnology, 2011
dc.description Cataloged from PDF version of thesis report.
dc.description Includes bibliographical references (page 55-60).
dc.description.abstract Bioethanol or biofuel as an alternative to fossil fuels has been expanded in the last few decades in the whole world. Saccharomyces cerevisiae is the choice of organism for ethanol production. Characterization of an ethanol producing ability and to optimization of ethanol production by a laboratory strain of yeast was attempted in the present study. Based on morphological and physiochemical characters, the yeast strain was identified to be Saccharomyces cerevisiae. The strain was moderately thermotolerant and ethanol tolerant as well as osmotolerant. It was resistant to cycloheximide at 0.0015g/100ml concentration but growth was inhibited in presence of Hydrogen peroxide. Ethanol producing capability of the Saccharomyces cerevisiae strain was studied using sugarcane molasses as substrate. The reducing sugar was estimated by DNS method and ethanol was estimated by redox titration. Fermentation was optimized with respect to temperature, reducing sugar concentration and pH. Analysis of fermentation characteristics under different substrate and environmental conditions, it was observed that reducing sugar concentration of 5%-6%, temperature of 30°Cand pH 6.0 were optimum for fermentation with maximum yield of ethanol. Maximum ethanol production was 11 % by free cells using the initial reducing sugar concentration 5.50% at 48 hrs under shaking condition. Immobilized yeast cells showed significant improvement of ethanol production. Under shaking condition, 12% ethanol was produced by immobilized cells using the reducing sugar concentration 6% at 48 hrs. Ethanol production was higher in shaking condition than that in stationery non shaking condition using the same environmental condition. Influence of boron, chromium, copper, magnesium chloride was investigated on ethanol production. Only chromium was found to show stimulatory effect on ethanol production. This selected strain could be potential strain for ethanol production from cane molasses. en_US
dc.description.statementofresponsibility Md. Abdul Quayum
dc.format.extent 65 pages
dc.publisher BRAC University en_US
dc.rights BRAC University thesis are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission.
dc.subject Biotechnology
dc.title Characterization of an ethanol producing yeast isolate and optimization of ethanol fermentation en_US
dc.type Thesis en_US
dc.contributor.department Department of Mathematical and Natural Science, BRAC University M. Biotechnology

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