植物乳杆菌最适生长底物解析及高密度培养工艺

为提高植物乳杆菌的增殖浓度,分别测定菌株在添加不同氮源、不同缓冲盐、不同浓度的MnSO4和不同促生长物质时菌株的生长浓度。结果表明,酵母类氮源是植物乳杆菌的最适氮源,缓冲盐在恒pH培养时对菌株生长无促进作用,锰浓度与最高活菌数呈正相关,在以酵母浸粉为氮源时植物乳杆菌培养不需要添加其他生长因子。进一步优化菌株的最适pH值和碳氮比,基于可耐受渗透压,优化恒pH培养和恒pH自动反馈补料培养基和培养工艺,得到各菌株的最适培养策略。3株菌的最适氮源添加量为40~45 g/L,MnSO4的最适添加量为0. 25 g/L,最适碳氮比为对数生长期生长速率被抑制时的碳氮消耗比。恒pH 5. 5自动反馈补料培养植物乳杆菌X1,活菌数达到4. 1×10^10CFU/mL;恒pH 5. 5分批培养植物乳杆菌N8,活菌数达到2. 9×10^10CFU/m L;恒pH 6. 0分批培养植物乳杆菌N9,活菌数达到6. 2×10^10CFU/mL。该研究结果的应用将显著提高植物乳杆菌的工业化生产效率。

Analysis of optimal growth substrate and high-density culture process of Lactobacillus plantarum

To increase the proliferation concentration of Lactobacillus plantarum(L. plantarum),the effects of different nitrogen sources,buffer salts,different concentrations of manganese sulfate and growth-promoting substances were studied. The results showed that yeast extract was the most suitable nitrogen source for L. plantarum. While buffer salt had no effect on the growth of the strain under p Hcontrolled condition. The concentration of manganese sulfate was positively correlated with the viable cell count that the strain could reach. No other growth-promoting substances was needed for the culture of L. plantarum when yeast extract was used as nitrogen source. The optimum pH and carbon-nitrogen ratio of the strain were further optimized. Based on the osmotic pressure that could be tolerated by the strain,the medium and process conditions for the culture with pH-controlled and the culture with automatic feedback feeding method were optimized to obtain the optimal culture strategy. The optimum concentration of nitrogen source and manganese sulfate for the three L. plantarum strains were 40-45 g/L and 0. 25 g/L,respectively. The optimum carbon-nitrogen ratio was the mass ratio of carbon source and nitrogen source consumed when the growth rate of L. plantarum was inhibited. The viable count of L. plantarum X1 reached 4. 1 × 10^10 CFU/mL when pH-controlled 5. 5 using the automatic feedback feeding method. The viable count of L. plantarum N8 reached 2. 9 × 10^10 CFU/mL using batch culture at pH 5. 5. The viable count of L. plantarum N9 reached 6. 2 × 10^10 CFU/mL using batch culture with pH-controlled 6. 0. The application of this research could significantly improve the industrial production efficiency of L. plantarum.