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영어

Bioethanol is a promising alternative biofuel for automobile. The current bioethanol is produced with corn and sugar cane, which are also used as foods and feeds. To replace the starch and sugar-based bioethanol, the 2nd and 3rd generation bioethanol technology have been developed using cellulosic and marine biomass, respectively.
Among marine biomass, red algae is mostly composed of cellulose and galactan. Galactan is a representative polymer consisting of D-galactose and anhydro-galactose. For efficient production of bioethanol from red algae, both glucose from cellulose and D-galactose from galactan should be fermented simultaneously. In this study, food-grade alcohol yeast, Saccharomyces cerevisiae was engineered to utilize both glucose and galactose simultaneously. A laboratory strain, S. cerevisiae D452-2 was subjected to evolutionary engineering by serial batch culture with 2-deoxy-D-glucose (an analog of D-glucose) and D-galactose. After five times serial cultures, the mutant strains were selected on YP solid medium containing both 2-deoxy-D-glucose and D-galactose. The fermentative characteristics of the yeast mutants were investigated in batch fermentation at different culture conditions.