Enhanced l-lactic acid production in Lactobacillus paracasei by exogenous proline addition based on comparative metabolite profiling analysis
Enhanced l-lactic acid production in Lactobacillus paracasei by exogenous proline addition based on comparative metabolite profiling analysis
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DOI：
10.1007/s00253-015-7136-6
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发表时间：
2016-03
影响因子：
5
通讯作者：
Xiwei Tian;Yonghong Wang;J. Chu;Y. Zhuang;Siliang Zhang
中科院分区：
文献类型：
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作者：
Xiwei Tian;Yonghong Wang;J. Chu;Y. Zhuang;Siliang Zhang
本研究研究了副干酪乳杆菌对渗透胁迫的细胞生理代谢反应。细胞脂肪酸组成和代谢物谱均以不饱和脂肪酸和环氧脂肪酸比例的增加以及一些特定的细胞内代谢物的积累为响应。同时，利用代谢物谱分析，合理、系统地发现潜在的渗透保护剂。因此，外源添加脯氨酸或天冬氨酸被证实是一种可行和有效的方法，以改善高渗胁迫下细胞在摇瓶中的生长。特别是在5-L培养体系下，添加2 g/L脯氨酸组的L -乳酸浓度在随后的16 h发酵过程中从108 g/L增加到150 g/L，而未添加脯氨酸组的L -乳酸浓度仅从110 g/L增加到140 g/L。在此阶段，添加脯氨酸的葡萄糖消耗速率达到3.49 g/L/h，比未添加脯氨酸的葡萄糖消耗速率提高35.8%。然而，极高的渗透压会极大地限制脯氨酸的渗透保护作用和l的渗透压阈值。降落伞重量约为3600 mOsm/kg。这表明脯氨酸主要是作为一种相容的溶质积累在细胞中进行高渗保存。利用代谢物谱来开发渗透保护剂和通过添加渗透保护剂来提高l-乳酸产量的策略将有可能为其他微生物和有机酸的生产提供新的见解。
This study investigated cell physiological and metabolic responses ofLactobacillus paracaseito osmotic stresses. Both cellular fatty acid composition and metabolite profiling were responded by increasing unsaturated and epoxy-fatty acid proportions, as well as accumulating some specific intracellular metabolites. Simultaneously, metabolite profiling was adopted to rationally and systematically discover potential osmoprotectants. Consequently, exogenous addition of proline or aspartate was validated to be a feasible and efficacious approach to improve cell growth under hyperosmotic stress in shake flasks. Particularly, with 5-L cultivation system,l-lactic acid concentration increased from 108 to 150 g/L during the following 16-h fermentation in 2 g/L proline addition group, while it only increased from 110 to 140 g/L in no proline addition group. Moreover, glucose consumption rate with proline addition reached 3.49 g/L/h during this phase, 35.8 % higher than that with no proline addition. However, extreme high osmotic pressure would significantly limit the osmoprotection of proline, and the osmolality threshold forL. paracaseiwas approximately 3600 mOsm/kg. It was suggested that proline principally played a role as a compatible solute accumulated in the cell for hyperosmotic preservation. The strategies of exploiting osmotic protectant with metabolite profiling and enhancingl-lactic acid production by osmoprotectant addition would be potential to provide a new insight for other microorganisms and organic acids production.