This technology involves a conditional cell wall-degrading yeast strain and its manufacturing method, created by replacing the OCH1 or CHS3 promoters—genes responsible for cell wall biosynthesis in Saccharomyces cerevisiae—with the MET3 promoter, which is repressed by methionine. When cultured in a methionine-supplemented medium, the yeast's cell wall weakens, allowing for the extracellular secretion of glutathione.
The thick, rigid cell wall of yeast hinders the recovery of intracellular products, necessitating physical, chemical, or enzymatic disruption processes that lead to product loss and increased production costs. Furthermore, intracellular glutathione accumulation triggers feedback inhibition of biosynthetic enzymes, plateauing yields. Alternative enzymatic production methods are limited by the need for external ATP and substrate amino acid supplementation.
Instead of disrupting growth-inhibiting genes, this technology uses a promoter that turns off only under specific conditions, allowing for normal growth while strictly controlling the cell wall degradation phenotype based on methionine presence. This significantly improves extracellular glutathione production efficiency without separate disruption steps, avoids feedback inhibition, and simplifies extraction. It can be applied to fermentation processes for whitening agents, supplements, and pharmaceutical raw materials, reducing both recovery costs and product loss.
This invention was developed with support from the Ministry of Science and ICT for research on constructing artificial regulatory circuits for the development of high-efficiency yeast cell factories.
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