The conversion of glycerol into 1,3-propanediol (1,3-PDO) has gained significant attention as a sustainable pathway within the biodiesel production chain. Limosilactobacillus reuteri, a bacterium capable of efficiently converting glycerol to 1,3-PDO, holds promise for this application. In industrial biotechnology, the development of kinetic models is important for bioreactor design, process analysis and scalability, supporting the advancement of biorefineries and the bioeconomy. This study focuses on investigating the kinetics of co-fermentation of glucose and glycerol by L. reuteri, utilizing data from previous batch culture experiments. Three different models were evaluated for these batch runs, and the parameters were adjusted using the Levenberg–Marquardt algorithm in conjunction with an integration method. The results from these previous batch experiments indicate that pH did not significantly influence the specific growth rate of the bacterium. However, as expected, reducing the temperature from 37 to 30°C resulted in a 60% reduction in the growth rate. Moreover, continuous co-fermentation experiments were conducted, and a simple kinetic model was proposed. The advantage of the continuous process is that the productivity of 1,3-PDO is 3.5 times higher compared with co-fermentation in batch mode. Notably, this study represents the first attempt to model continuous co-fermentation under a range of dilution rates (0.25–0.9 h⁻¹), identifying a dilution rate of 0.5 h⁻¹ as the optimal condition to produce 1,3-PDO, considering productivity and substrate conversion. The findings of this research contribute valuable insights for future investigations on the viability of 1,3-PDO production from glycerol, particularly within the context of waste valorization.

中文翻译：

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1,3-丙二醇生产商罗伊氏柠檬酸杆菌进行甘油和葡萄糖共发酵：分批和连续培养的动力学研究

将甘油转化为 1,3-丙二醇 (1,3-PDO) 作为生物柴油生产链中的可持续途径受到了广泛关注。罗伊氏柠檬酸乳杆菌是一种能够有效地将甘油转化为 1,3-PDO 的细菌，有望实现这一应用。在工业生物技术中，动力学模型的开发对于生物反应器设计、过程分析和可扩展性非常重要，支持生物精炼和生物经济的进步。本研究的重点是利用之前批量培养实验的数据，研究罗伊氏乳杆菌共发酵葡萄糖和甘油的动力学。针对这些批量运行评估了三种不同的模型，并使用 Levenberg-Marquardt 算法结合积分方法调整参数。先前批次实验的结果表明 pH 值并未显着影响细菌的比生长速率。然而，正如预期的那样，将温度从 37°C 降低到 30°C 会导致生长速度下降 60%。此外，进行了连续共发酵实验，并提出了一个简单的动力学模型。连续工艺的优点是1,3-PDO的生产率比间歇模式共发酵高3.5倍。值得注意的是，这项研究首次尝试在一系列稀释率（0.25-0.9 h ^{-1 ）下模拟连续共发酵，确定0.5 h -1}的稀释率​​是生产 1,3-PDO 的最佳条件，考虑生产率和底物转化率。这项研究的结果为未来研究从甘油生产 1,3-PDO 的可行性提供了宝贵的见解，特别是在废物增值的背景下。