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

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.