一株具有藻毒素清除功能的干酪乳杆菌细胞高密度发酵条件优化

为提高一株具有藻毒素清除能力的干酪乳杆菌Lactobacillus casei BBEi0—212单位体积的活菌数，针对其营养需求，研究了不同碳源、氮源、缓冲盐、微量元素及生长因子对该菌株生长情况及发酵特性的影响。通过响应面法对碳源、氮源、生长因子等进行优化，获得最佳培养基配方为：α-乳糖43．8g/L，酵母膏79．5g/L，无水乙酸钠13．12g／L，冰醋酸9．17mL／L，MnSO4·H20190mg／L，吐温-805．15mL/L。经37℃培养18h，菌体干重达到4．97g/L，比在普通MRS培养基中（1．32g／L）提高近4倍。基于乳酸菌发酵过程中的产酸特性，通过外源添加5g／L谷氨酸，促使菌体浓度进一步提高15％，并提前1．2h进入生长稳定期。上述研究结果为食品行业重要生产菌株干酪乳杆菌的高密度培养技术提供了可借鉴的研究思路。

Optimization of high cell-density fermentation of Lactobacillus casei with function of removing microcystin

In order to improve the viable cells of Lactobacillus casei BBE10-212, the effects of differem carbon sources, nitrogen sources, buffer salts, microelements and growth factors on the cell growth were studied according to the nutritional requirements of lactic acid bacteria （LAB）. Furthermore, as the most significant factors, the composition of carbon sources, nitrogen sources and growth elements were optimized using response surface method, and the optimal result was a-lactose 43.8 g/L, yeast extract 79.5 g/L, sodium acetate anhydrous 13.12 g/L, acetic acid 9.17 mL/L, MnSO4 ＂H20 190 rng/L and tween-80 5.15 rnL/L. After cultivated in this medium for 18 h at 37 ℃, the cell density was 4.97 g/L, which was about 4 times higher than in MRS （1.32 g/L）. Meanwhile, aimed to modulate the characteristic of LAB with acid production, 5 g/L glutamic acid was used to improve the cell density by 15%, and to shorten 1.2 h to enter the stationary phase. All the results above provide a novel way to the high density cultivation of Lactobawillus casei.