Significantly increase of glycolytic flux and pyruvate productivity in Torulopsis glabrata by heterologous expression of NADH alternative oxidase

Abstract:

Abstract: [Objective] This study aimed at increasing the glycolytic flux and pyruvate productivity in Torulopsis glabrata with glucose as carbon source. [Methods] For this target, we introduced a mitochondrial located alternative oxidase encoded by Histoplasma capsulatum AOX1 gene into T. glabrata, and a mutant strain named as AOX with total NADH oxidase activity was 1.8-fold higher than that of the parent stain, was achieved. [Results] The heterologous expression of NADH alternative oxidase resulted in decrease of the dry cell weight and fermentation time by 20.3% and 10.7%, but the specific rate of glucose consumption and pyruvate production increased 34.7% and 54.1% higher, respectively. The reasons for high glycolytic flux were the intracellular NADH/NAD+ ratio and ATP concentration decreased 74.7% and 52.9% respectively, the specific activity of phosphofructokinase, pyruvate kinase increased 185.0% and 28.1%. [Conclusion] Introduction of a novel NADH oxidation pathway by alternative oxidase can efficiently increase the rate of glucose consumption and the target metabolite productivity.