干酪乳杆菌XJL发酵废弃烟梗产L-乳酸的Plackett-Burman优化

目的寻求L-乳酸发酵的廉价基质和资源化利用废弃烟梗。方法以废弃烟梗为材料制备水提取液(tobacco stem extraction,TSE),以菌株XJL发酵废弃烟梗提取液制备L-乳酸,通过Plackett-Burman优化设计实验对影响菌株XJL发酵废弃烟梗提取液制备L-乳酸的相关变量因素进行分析评估。结果所选10个相关变量因素中,当发酵时间为24 h时,酵母粉和碳酸钙是影响菌株XJL发酵制备L-乳酸的重要正效应因子,当发酵时间为42 h时,酵母粉、果糖、磷酸氢二钠和碳酸钙是影响菌株XJL发酵制备L-乳酸的重要正效应因子。在Plackett-Burman优化实验设计中,发酵时间为24 h和42 h时,L-乳酸的最高产率分别为307.5 g/kg和315.0g/kg。结论在Plackett-Burman实验中,发酵时间的延长对L-乳酸产率的提高影响不大,营养添加物能够提高L-乳酸的产量。

Plackett-Burman optimization of L-lactic acid produced by fermentation of waste tobacco stems by Lactobacillus casei XJL

Objective To seek low-cost substrate for L-lactic acid fermentation and resource utilization of waste tobacco stems. Methods Tobacco stem extraction (TSE) were prepared from waste tobacco stem and L-lactic acid was produced by fermentation of TSE by Lactobacillus casei XJL. Besides, Plackett-Burman design was performed to evaluate some variables which were relevant to L-latic acid production of Lactobacillus casei XJL. Results Among ten selected variables, yeast powder and CaCO3 were found to significantly influence L-latic acid production via Plackett-Burman design and the following statistic analysis with the culture time at 24 h, whereas the key factors were yeast powder, fructose, sodium dihydrogen phosphate and CaCO3 at 48 h. Under Plackett-Burman design conditions, the maximum production of L-latic acid at 24 h and 48 h reached to 307.5 g/kg and 315.0 g/kg. Conclusion The fermentation time had little effect on L-lactic acid yield, while nutritional additives can improve the production of L-lactic acid.