Bioprocess Engineering, Wageningen University, Wageningen, The Netherlands.
Bioprocess Biosyst Eng. 2012 May;35(4):591-603. doi: 10.1007/s00449-011-0632-x. Epub 2011 Sep 30.
The production of lipids by oleaginous yeast and fungi becomes more important because these lipids can be used for biodiesel production. To understand the process of lipid production better, we developed a model for growth, lipid production and lipid turnover in submerged batch fermentation. This model describes three subsequent phases: exponential growth when both a C-source and an N-source are available, carbohydrate and lipid production when the N-source is exhausted and turnover of accumulated lipids when the C-source is exhausted. The model was validated with submerged batch cultures of the fungus Umbelopsis isabellina (formerly known as Mortierella isabellina) with two different initial C/N-ratios. Comparison with chemostat cultures with the same strain showed a significant difference in lipid production: in batch cultures, the initial specific lipid production rate was almost four times higher than in chemostat cultures but it decreased exponentially in time, while the maximum specific lipid production rate in chemostat cultures was independent of residence time. This indicates that different mechanisms for lipid production are active in batch and chemostat cultures. The model could also describe data for submerged batch cultures from literature well.
产油酵母和真菌产生的脂质变得越来越重要，因为这些脂质可用于生物柴油生产。为了更好地理解脂质生产过程，我们开发了一个用于浸没式分批发酵中生长、脂质生产和脂质周转的模型。该模型描述了三个连续的阶段：当同时存在 C 源和 N 源时的指数生长，当 N 源耗尽时的碳水化合物和脂质生产，以及当 C 源耗尽时积累的脂质的周转。该模型通过使用两种不同初始 C/N 比的真菌 Umbellopsis isabellina（以前称为 Mortierella isabellina）的浸没式分批培养进行了验证。与相同菌株的恒化器培养物的比较表明，脂质生产存在显著差异：在分批培养中，初始比脂质生产速率几乎比恒化器培养物高四倍，但随着时间的推移呈指数下降，而恒化器培养物中的最大比脂质生产速率与停留时间无关。这表明在分批和恒化器培养物中，脂质生产的机制不同。该模型还可以很好地描述文献中浸没式分批培养物的数据。
