6-磷酸葡萄糖酸脱氢酶在产油细菌浑浊红球菌PD630脂质积累中的作用

Role of 6-Phosphogluconate Dehydrogenase in Lipid Accumulation of Oleaginous BacteriaRhodococcus opacusPD630

DOI：10.3969/j.issn.1673-1689.2019.03.009

中文关键词: 6-磷酸葡萄糖酸脱氢酶 脂质生物合成 NADPH 产油微生物 浑浊红球菌PD630

英文关键词: 6-phosphogluconate dehydrogenase,lipid biosynthesis,NADPH,oleaginous microor- ganisms,Rhodococcus opacusPD630

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中文摘要:

产油微生物脂质合成的过程已基本清晰：乙酰辅酶A和还原力NADPH在脂肪酸合酶（FAS）的作用下合成脂肪酸。产油微生物菌体内主要有苹果酸酶（ME）、葡萄糖-6-磷酸脱氢酶（G6PDH）、6-磷酸葡萄糖酸脱氢酶（6PGDH）和异柠檬酸脱氢酶（ICDH）为其脂质合成提供所需还原力NADPH。为了研究6PGDH在浑浊红球菌PD630（Rhodococcus opacusPD630）脂质积累中的作用，作者将编码氧化磷酸戊糖路径（oxPPP）中6PGDH的基因gnd在R. opacus PD630中过表达。结果表明，与对照菌株相比较，过表达gnd的重组菌株总脂肪酸含量提高了20%~30%，且6PGDH酶活力和gnd的转录水平也显著提高。由此可见，6PGDH在R. opacus PD630脂质合成中具有重要的作用，能为其提供所需的还原力NADPH，以促进其脂质的积累。

英文摘要:

The process of lipid biosynthesis in oleaginous microorganisms is basically clear：both the reducing power NADPH and the building block acetyl-CoA are required by fatty acid synthase（FAS） to synthesize fatty acids. In oleaginous microorganisms，the main enzymes involved in the provision of reducing power NADPH are malic enzyme（ME），glucose-6-phosphate dehydrogenase（G6PDH），6-phosphogluconate dehydrogenase（6PGDH），and isocitrate dehydrogenase（ICDH）. In this study，the genes coding for 6-phosphogluconate dehydrogenase（gnd） from the oxidative pentose phosphate pathway（oxPPP） were over-expressed in the oleaginous bacteriaRhodococcus opacusPD630 to analyze its effect on lipid accumulation. The results showed that over-expression ofgndincreased the content of lipid（w/w） by 20%~30% compared with the control strain. Meanwhile，the activities and the mRNA levels of 6PGDH in the overexpressing strains were higher than that of the control. Therefore，it was concluded that 6PGDH enhanced the lipid accumulation through promoting the generation of NADPH in the oleaginous bacteriaR. opacusPD630.

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