Application of degradable plastics is the most critical solution to plastic pollution. As the precursor of biodegradable plastic PLA (polylactic acid), efficient production of l‐lactic acid is vital for the commercial replacement of traditional plastics. Bacillus coagulans H‐2, a robust strain, was investigated for effective production of l‐lactic acid using long‐term repeated fed‐batch (LtRFb) fermentation. Kinetic characteristics of l‐lactic acid fermentation were analyzed by two models, showing that cell‐growth coupled production gradually replaces cell‐maintenance coupled production during fermentation. With the LtRFb strategy, l‐lactic acid was produced at a high final concentration of 192.7 g/L, on average, and a yield of up to 93.0% during 20 batches of repeated fermentation within 487.5 h. Thus, strain H‐2 can be used in the industrial production of l‐lactic acid with optimization based on kinetic modeling.

中文翻译：

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凝结芽孢杆菌菌株长期重复补料分批 (LtRFb) l-乳酸发酵的动力学特征

应用可降解塑料是解决塑料污染最关键的办法。作为可生物降解塑料PLA（聚乳酸）的前体，L-乳酸的高效生产对于传统塑料的商业替代至关重要。凝结芽孢杆菌 H-2 是一种强大的菌株，研究人员利用长期重复补料分批 (LtRFb) 发酵有效生产 L-乳酸。通过两个模型分析了L-乳酸发酵的动力学特征，表明发酵过程中细胞生长耦合生产逐渐取代了细胞维持耦合生产。采用LtRFb策略，在487.5小时内进行20批重复发酵时，L-乳酸的终浓度平均为192.7 g/L，产率高达93.0%。因此，通过基于动力学模型的优化，菌株H-2可用于L-乳酸的工业生产。