Abstract:

Based on lab scale （3 L） experiments, the pilot plant scale test （30 L to 150 L） of the high cell density culture of L. casei Zhang was studied toget the optimal fermentation technology for industrial production. Under optimized culture conditions, the viable count of fermented liquid was 2.9 × 10^10cfu/mL and there was no significant different between pilot plant test and lab scale test. The kinetic models of growth and glucose consumption for L. casei Zhang were constructed using origin7.5 software based on the equations of ＂logistic equation＂ and fit well with the experimental data, with an average error of less than 10%. These models could forecast the actual fermentation process. Preliminary study was carried out on the influences of centrifugation and freeze-drying processes on cells after fermentation. Although the average viable cell count of the lyophilized powder was 2.65 × 10^11 cfu/g, which could meet the requirements of the probiotics and starter cultures, only 49.97% of L. casei Zhang cells were survived from freeze drying. So it＇s necessarily to make further study on how to improve the survival rate of L. casei Zhang during freeze drying.

Key words: Lactobacillus casei Zhang, high cell density culture, pilot plant test, kinetics

摘要：

在益生菌L.caseiZhang高密度培养小试（3L）基础上,进行30L到150L逐级放大中试生产工艺的研究以确定规模化生产工艺。在优化的发酵工艺下,150L规模发酵菌体密度可达2 .9×10^10cfu/mL,与小试水平无差异。采用origin7.5软件在logistic equation基础上建立L.caseiZhang的生长和葡萄糖代谢动力学模型,模型与试验值拟合良好,平均误差小于10%,能够较好地反应发酵过程。初步探讨发酵后菌体的离心和冷冻干燥过程对菌体的影响,虽然发酵液经离心收集菌体后冷冻干燥可得到平均活菌数2.65×10^11cfu/g的菌粉,能够满足益生菌制剂和发酵剂对高活菌数的要求,但冻干前后活菌得率仅49.97%。有必要针对L.casei Zhang的冻干保护剂和冻干工艺进一步优化,以提高菌体存活率得到更高菌体浓度的益生菌粉。

关键词: Lactobacillus casei Zhang 高密度发酵 中试 动力学