Mutation breeding for productive yeast strains through a novel method: High-energy-pulse-electron-beam

Abstract

High-energy-pulse-electron beam (HEPE) has primarily been used in pulse radiolysis and material surface modification to date. In this study, we applied HEPE in yeast (Saccharomyces cerevisiae) breeding and investigated its biological effects on plasmid DNA and yeast plasma membrane. A thermo-tolerant and high- ethanol-yield yeast strain YE2 was obtained after HEPE radiation and temperature selection, with optimum temperature improved 2 °C and ethanol yield improved 25.5%, suggesting that it is a promising candidate for cellulose-derived ethanol production. DNA-lesion analysis showed that the G-value of HEPE radiation for double-strand breaks (DSB) formation is 2.5 × 10-10 Gy-1 Da-1, which is 5 times that of γ-radiation, while there was only 12.1% plasma membrane damage found even at high dosage of 750 Gy.