异源表达NADH选择性氧化酶提高光滑球拟酵母酵解速率及丙酮酸生产强度

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

摘要:

摘要：【目的】为进一步提高光滑球拟酵母(Torulopsis glabrata)葡萄糖代谢速率及丙酮酸生产强度。【方法】将源于荚膜胞浆菌(Histoplasma capsulatum)的编码选择性氧化酶的AOX1基因过量表达于T. glabrata中，获得了一株线粒体内NADH氧化途径发生改变且胞内总NADH 氧化酶活性提高1.8倍的重组菌株AOX。【结果】与出发菌株CON比较，细胞浓度以及发酵周期降低了20.3%和10.7%，而平均比葡萄糖消耗速率和丙酮酸合成速率分别提高了34.7%和54.1%。其原因

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.