Department of Systems Biology, Building 223, Soeltofts Plads, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark.
AMB Express. 2013 Oct 3;3(1):58. doi: 10.1186/2191-0855-3-58.
Yarrowia lipolytica is an attractive host for sustainable bioprocesses due to its ability to utilize a variety of carbon substrates and convert them to a range of different product types (including lipids, organic acids and polyols) under specific conditions. Despite an increasing number of applications for this yeast, relatively few studies have focused on uptake and metabolism of carbon sources, and the metabolic basis for carbon flow to the different products. The focus of this work was quantification of the cellular performance of Y. lipolytica during growth on glycerol, glucose or a mixture of the two. Carbon substrate uptake rate, growth rate, oxygen utilisation (requirement and uptake rate) and polyol yields were estimated in batch cultivations at 1 litre scale. When glucose was used as the sole carbon and energy source, the growth rate was 0.24 h-1 and biomass and CO2 were the only products. Growth on glycerol proceeded at approximately 0.30 h-1, and the substrate uptake rate was 0.02 mol L-1 h-1 regardless of the starting glycerol concentration (10, 20 or 45 g L-1). Utilisation of glycerol was accompanied by higher oxygen uptake rates compared to glucose growth, indicating import of glycerol occurred initially via phosphorylation of glycerol into glycerol-3-phosphate. Based on these results it could be speculated that once oxygen limitation was reached, additional production of NADH created imbalance in the cofactor pools and the polyol formation observed could be a result of cofactor recycling to restore the balance in metabolism.
解脂耶氏酵母因其能够利用多种碳源并在特定条件下将其转化为多种不同类型的产品（包括脂质、有机酸和多元醇）而成为可持续生物工艺的有吸引力的宿主。尽管这种酵母的应用越来越多，但相对较少的研究关注碳源的摄取和代谢，以及碳流到不同产品的代谢基础。这项工作的重点是定量研究解脂耶氏酵母在甘油、葡萄糖或两者混合物上生长时的细胞性能。在 1 升规模的分批培养中估计了碳底物摄取率、生长速率、氧利用率（需求和摄取率）和多元醇产率。当葡萄糖作为唯一的碳源和能源时，生长速率为 0.24 h-1，生物量和 CO2 是唯一的产物。在甘油上的生长速度约为 0.30 h-1，无论起始甘油浓度（10、20 或 45 g L-1）如何，底物摄取率均为 0.02 mol L-1 h-1。与葡萄糖生长相比，甘油的利用伴随着更高的氧气摄取速率，表明甘油最初通过甘油磷酸化为甘油-3-磷酸进入细胞。基于这些结果可以推测，一旦达到氧气限制，额外的 NADH 产生会导致辅酶池失衡，观察到的多元醇形成可能是辅酶回收以恢复代谢平衡的结果。
