earticle

영어

Ethanol has a toxic effect on the cell that inhibits the cellular growth and metabolism. Therefore, ethanol resistance of the cell is a considerable factor in the fermentation process and for this reason the goal of this study was to develop genetically engineered mutants having improved ethanol tolerance. In the previous study, an ethanol producing Escherichia coli BL21 was developed, by introducing pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB)
into the cell and heat shock genes, BEM1 and SOD2 from Saccharomyces cerevisiae, were inserted into the mutated Eschericia coli BL21 in this study. Finally, we could have three different Escherichia coli strains; the ethanol producing strain, BEM1 gene inserted strain, and SOD2 gene inserted strain. By comparing the three different strains, we were able to measure the functions of
heat shock genes, BEM1 and SOD2, and also their functions in ethanol tolerance. The three strains were tested by measuring the cellular growth in various ethanol concentrations, 0%, 1%, 3%, 5% (w/v) ethanol concentration medium. As a result, ethanol resistance mutants showed about two times higher cell growth rate than the ethanol producing mutant in the 5% ethanol
concentration medium. In addition, ethanol production yields of the ethanol resistance mutants remained at similar level to the ethanol producing mutant; 2.02g/l for SOD2 inserted mutant, 1.57g/l for BEM1 inserted mutant and 2.03g/l for the ethanol producing mutant.