Fatemeh Sheikhi - Sugarcane Training and Research Institute of Khuzestan
Khosrow Rostami - Iranian Research Organization for Science and Technology
Mehrdad Zain - Iranian Research Organization for Science and Technology
Mohammad Ali Asadollahi - Industrial Biotechnology, University of Isfahan

Background and Aim: Butanol is a class of chemicals, which has several applications such as fuel, industrial solvent, etc. Saccharomyces cerevisiae, in particular, is a well-studied organism with a long history of industrial use; e.g. in brewing and ethanol production. Different isomers of butanol exhibit different extents of toxicity. 1-butanol being the most toxic with concentrations above 1.5-2% (v/v), is inhibitory for most cells including the native 1-butanol producers. One of the reasons for this is probably that 1-butanol is a hydrophobic molecule with the strongest ability to permeate and/or interact with the cellular membrane components. Random mutagenesis by physical mutagens such as UV radiation seems to be an uncomplicated method for yeast strain improvement.Methods: 0.1 ml of a suspension of about 1.7× 108 cells/ml of industrial strain Ethanol red of Saccharomyces cerevisiae was plated on YEPD-1-butanol agar medium, containing (g/l): yeast extract,10; peptone, 20; dextrose, 20; 1-butanol, 2%, 2.25% and 2.5% (v/v); agar, 20; pH 5.5. The plates were exposed to short wavelength U.V. light, (280 nm) from a distance of 20cm by using a 30W germicidal U.V. lamp in different times up to 180 seconds, until a survival of about 0.01% was obtained.Results:Mutants that were resistant against 1-butanol (2%, 2.25% and 2.5%) were selected.Conclusion:In this research, the procedures of creating a novel mutant of Saccharomyces cerevisiae which was screened from a mutated population of yeast, which was treated by UV light and screened in different concentration of 1-butanol is described.

Saccharomyces cerevisiae ,UV radiation ,1- butanol tolerance