Lipomyces starkeyi has been widely regarded as a promising oleaginous yeast with broad industrial application prospects because of its wide substrate spectrum, good adaption to fermentation inhibitors, excellent fatty acid composition for high-quality biodiesel, and negligible lipid remobilization. However, the currently low experimental lipid yield of L. starkeyi prohibits its commercial success. Metabolic model is extremely valuable to comprehend the complex biochemical processes and provide great guidance for strain modification to facilitate the lipid biosynthesis. A small-scale metabolic model of L. starkeyi NRRL Y-11557 was constructed based on the genome annotation information. The theoretical lipid yields of glucose, cellobiose, xylose, glycerol, and acetic acid were calculated according to the flux balance analysis (FBA). The optimal flux distribution of the lipid synthesis showed that pentose phosphate pathway (PPP) independently met the necessity of NADPH for lipid synthesis, resulting in the relatively low lipid yields. Several targets (NADP-dependent oxidoreductases) beneficial for oleaginicity of L. starkeyi with significantly higher theoretical lipid yields were compared and elucidated. The combined utilization of acetic acid and other carbon sources and a hypothetical reverse β-oxidation (RBO) pathway showed outstanding potential for improving the theoretical lipid yield. The lipid biosynthesis potential of L. starkeyi can be significantly improved through appropriate modification of metabolic network, as well as combined utilization of carbon sources according to the metabolic model. The prediction and analysis provide valuable guidance to improve lipid production from various low-cost substrates.

中文翻译：

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Lipomyces starkeyi 的代谢模型，用于预测来自不同低成本底物的脂肪生成潜力

Lipomyces starkeyi因其底物谱广、对发酵抑制剂的良好适应性、优质生物柴油的优良脂肪酸组成以及可忽略的脂质再动员被广泛认为是一种具有广阔工业应用前景的有前途的产油酵母。然而，目前 L. starkeyi 的低实验脂质产量阻碍了其商业成功。代谢模型对于理解复杂的生化过程非常有价值，并为菌株修饰以促进脂质生物合成提供了很好的指导。基于基因组注释信息构建了L. starkeyi NRRL Y-11557的小规模代谢模型。根据通量平衡分析 (FBA) 计算葡萄糖、纤维二糖、木糖、甘油和乙酸的理论脂质产量。脂质合成的最佳通量分布表明，磷酸戊糖途径 (PPP) 独立满足 NADPH 对脂质合成的必要性，导致脂质产率相对较低。比较并阐明了有利于 L.starkeyi 产油能力且理论脂质产量显着更高的几个目标（NADP 依赖性氧化还原酶）。乙酸和其他碳源的联合利用以及假设的逆 β-氧化 (RBO) 途径显示出提高理论脂质产量的巨大潜力。根据代谢模型，通过适当修改代谢网络，以及碳源的联合利用，可以显着提高L.starkeyi的脂质生物合成潜力。