Momoko Tachibana
Ritsumeikan University, Japan
Title: Assimilation of amino acids by autophagy-defective mutants of Saccharomyces cerevisiae
Biography
Biography: Momoko Tachibana
Abstract
Whey is a by-product of cheeses and rich in nutrients. Although, whey had been thrown away into the river untill the 1980’s, it has been banned to stop eutrophication and to preserve environment. Therefore, various methods for effectively utilizing whey waste have been proposed. In our laboratory, we have been developing alcoholic drink made from whey for the better use of it. It is known that amino acids contained in alcoholic drink have an influence on its taste. We have been interested in an ability of amino acid assimilation of yeast from the view point of alcohol fermentation.
In the present study, we have constructed the deletion mutant of autophagy- related gene in Saccharomyces cerevisiae to compare the capability of amino acid assimilation between wild- and mutant-yeast. Autophagy- related genes are involved in the intracellular recycling of amino acids. Among them, we have focused on ATG1 gene because it is the trigger for autophagy in starvation. Because autophagy-defective mutants are considered to be lack of recycling ability of amino acids, external amino acids would much more positively be taken up by mutant-yeast for life support than wild-yeast. ATG1-defective mutant of S. cerevisiae BY4742 was constructed by homologous recombination method. The wild- and mutant-yeasts fermented and compared between them the total amino acids, ethanol concentration, and glucose. As a result, little differences of medium constituents between the wild- and mutant-yeasts have been observed in the fermentation under nutrient rich condition like YPD medium. Experiments under various fermentation conditions are in progress.