Fatemeh Sheikhi - Sugarcane Training and Research Institute, Khuzestan, Iran. Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran.
Khosrow Rostami - Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Mehrdad Azin - Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Mohammad Ali Asadollahi - Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan
Mansour Ebrahimi - Bioinformatics Research Group, Green Research Center, University of Qom, Iran
Payam Ghiaci - Swedish National Research Institute

Background and Aim : There are crucial factors in the bioethanol production process that affectproduction efficiency. Accumulation of ethanol during the fermentation process and the inhibitoryeffect on growth are inevitable. Saccharomyces cerevisiae is widely used for industrial productionof ethanol. The tolerance to high ethanol concentrations, high-temperature is essential for processperformance. Any increase in ethanol tolerance in the commercial strains led to faster and morecomplete fermentation, and may also allow the production of more alcohol. .Methods : In the present study, to improve ethanol production the in the commercial “Razi۱۷۰”strain, the parent strain was mutated physically and chemically. The mutants were screened using۱-butanol containing medium. The primary parent and the mutants were evolved within ۱۴۴ dayswith evolutionary engineering strategy, while ethanol tolerance phenotype of selected strains wasinvestigated.Results : According to the increase in the maximum growth rate, ۸ strains were selected includingparental strain and mutants, and the amounts of ethanol production of these strains were evaluatedafter evolutionary adaptation tests. Ethanol production of R۱۱۱ and R۱۱۳ which were mutatedwith EMS and UV before the adaptive evolution test and then evolved at ۹ and ۱۱% v/v ethanol,respectively, was improved from ۰.۰۳۳ h-۱ to ۰.۱۱۲ h-۱ and ۰.۰۹۸ h-۱, respectivelyConclusion : Evolutionary engineering, is a narrow-experimental evolution that mimics thisnatural phenomenon in laboratory towards the desired phenotype that has been used excessivelysince two decades ago, and it has an extensive capabilities in creating capable strains in order toincrease ethanol tolerance in industrial strains. To increase the genetic diversity of the primarypopulation, before starting the adaptive evolution experiments, mutation with ethyl methanesulfonate was used, which was more efficient than ultraviolet radiation in accelerating theevolution process to achieve the desired phenotype.

Evolutionary engineering, Ethanol production, Mutation, Saccharomyces cerevisiae