School of Bioengineering, Dalian University of Technology, Dalian, China.
Chemical Control Technology Key Laboratory of Liaoning Province, Institute of Information and Engineering, Shenyang University of Chemical and Technology, Shenyang, China.
Biotechnol Prog. 2022 Jan;38(1):e3225. doi: 10.1002/btpr.3225. Epub 2021 Nov 23.
In utilizing glycerol to produce 1,3-propanediol by microbial fermentation, the problems of low utilization rate and poor production performance need to be addressed. Based on the analysis of a mathematical model for 1,3-propanediol production from glycerol by Klebsiella pneumoniae, this study theoretically investigated the effects of the dilution rate and the initial glycerol concentration in a two-stage fermentation process and the feasibility of applying the feedback control methods. First, the optimal operation conditions of initial glycerol concentration and dilution rate were obtained. Through the use of feedback control theory, a control strategy for dilution rate was designed and optimized to shorten the settling time (time required for fermentation to reach stability) from 60.92 to 36.68 h for the first reactor, and from 53.66 to 22.68 h for the second reactor. In addition, the yield of 1,3-propanediol in both two reactors reached up to 0.5 g·g . The simulation results indicated that the feedback control strategy for dilution rate increased the product concentration, reduced the residual glycerol in the fermentation broth, and greatly improved the performance of the fermentation. A feeding strategy of automatic control for dilution rate has been established and will be applied as an effective guiding scheme in automatic continuous fermentations for production of 1,3-propanediol.
在利用甘油通过微生物发酵生产 1,3-丙二醇的过程中，存在利用率低和生产性能差等问题。本研究基于对肺炎克雷伯氏菌发酵生产 1,3-丙二醇的数学模型的分析，从理论上探讨了两阶段发酵过程中稀释率和初始甘油浓度的影响以及应用反馈控制方法的可行性。首先，得到了初始甘油浓度和稀释率的最佳操作条件。通过反馈控制理论，设计并优化了一种稀释率控制策略，使第一个反应器的稳定时间（发酵达到稳定所需的时间）从 60.92 小时缩短到 36.68 小时，第二个反应器的稳定时间从 53.66 小时缩短到 22.68 小时。此外，两个反应器中 1,3-丙二醇的产率均达到 0.5 g·g 。模拟结果表明，稀释率反馈控制策略提高了产物浓度，降低了发酵液中残留的甘油，极大地提高了发酵性能。建立了一种自动控制的稀释率进料策略，并将其应用于 1,3-丙二醇的自动连续发酵中，作为一种有效的指导方案。
