Simultaneous point and structural mutations in engineered yeast Saccharomyces cerevisiae improve carotenoid production

Engineered Saccharomyces cerevisiae is known to produce β-carotene, an antioxidant. In a previous study, we developed a technique for the efficient establishment of diverse mutants through the simultaneous introduction of point and structural mutations into the yeast genome. This study aimed to improve the β-carotene productivity of these engineered yeasts via mutagenesis. Point and structural mutations were simultaneously introduced into β-carotene-producing engineered yeast, and hydrogen peroxide-resistant mutants were obtained. These mutants exhibited a higher β-carotene production capacity than the parent strain. The top-performing mutant, HP100_74, produced 37.6 mg/L of β-carotene, a value 1.9 times higher than that of the parental strain (20.1 mg/L). Gene expression analysis confirmed an increased expression of multiple genes in the glycolysis, mevalonate, and β-carotene synthesis pathways, as well as a decreased expression of ERG9 , which functions in a competitive pathway for β-carotene production in the mutant strain. The simultaneous introduction of point and structural mutations represents a simple yet effective method for achieving mutagenesis in yeasts. This technique is expected to be widely applied in the future to produce chemicals via metabolic engineering of S. cerevisiae .