Microbial Butanol Production-Tolerance Improvement

Microbial Butanol Production- Tolerance Improvement

     Despite huge amount of investment and technological developments in bioethanol production industry, ethanol is not an ideal substitute for gasoline because of its high water content and low energy density comparative to gasoline. Looking for a better replacement, butanol proves superior characteristics relative to ethanol. Butanol by containing 22% oxygen in its structure leads to more complete fuel combustion, when used as a fuel extender. Longer alkyl chain of butanol equates to an easier solvent extraction and higher energy content per weight. However, it is still not certain that butanol can technically replace ethanol (as a fuel) due to the big difference in cell toxicity of solvents.In addition, two of butanol isomers, 1-butanol (n-butanol) and 2-butanol (sec-butanol), also have different physical and chemical characteristics which leads to distinct cell toxicity.Beside applying Clostridia family, there have been various attempts to produce biobutanol by either using Escherichia Coli and Saccharomyces cerevisiae cells as host. In this work, to improve butanol tolerance, running sequential batch cultures led to 2-butanol tolerance improvement of a yeast strain for more than 20%. The mutated strain is capable to grow in a medium including 3% 2-buatnol.  

Keywords: 2-butanol, biofuel, S. cerevisiae