State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, P. R. China.
ACS Synth Biol. 2023 Jun 16;12(6):1750-1760. doi: 10.1021/acssynbio.3c00046. Epub 2023 May 11.
Increasing carbon flux toward target metabolites is important in improving microbial productivity and economic value. To improve the efficiency of lipid production in , we knocked down genes for trehalose-6-phosphate synthetase () and phosphoenolpyruvate carboxykinase () in the major pathways for saccharide synthesis. The knockdown of reduced trehalose content by an average of 31.87%, while the knockdown of reduced the total saccharide content by 28.6%, and both recombinant strains showed more than 20% increased lipid yield. Trehalose plays a vital role in stress resistance, but a higher polyunsaturated fatty acid-rich lipid content was found to partly compensate for the loss of trehalose after knockdown. As compared with knockdown, the knockdown of gave better lipid production by bringing forward the time to maximum lipid yield by three days in a scale-up test. The arachidonic acid yield after the knockdown reached 1.23 g/L, which was 39.9% higher than that of the original strain. The present research provided an efficient strategy for redistributing carbon flux among different metabolites and therefore promoted microbial lipid yield in a shorter fermentation period.
提高目标代谢物的碳通量对于提高微生物生产力和经济价值非常重要。为了提高微生物生产油脂的效率，我们敲除了糖合成主要途径中的海藻糖-6-磷酸合成酶（TPS）和磷酸烯醇丙酮酸羧激酶（PCK）基因。TPS 的敲低使海藻糖含量平均降低了 31.87%，而 PCK 的敲低使总糖含量降低了 28.6%，这两个重组菌株的油脂产量均提高了 20%以上。海藻糖在应激抗性中起着至关重要的作用，但发现在敲低 后，较高的多不饱和脂肪酸丰富的脂质含量部分弥补了海藻糖的损失。与敲低相比，在扩大规模试验中，敲低 将最大油脂产量出现的时间提前了三天，从而使油脂产量得到了更好的提高。敲低后的花生四烯酸产量达到了 1.23g/L，比原始菌株提高了 39.9%。本研究提供了一种在不同代谢物之间重新分配碳通量的有效策略，从而在更短的发酵周期内提高了微生物油脂产量。
