乳酸菌的高密度培养及发酵剂保藏技术的初步研究

Study on High Cell Density Culture of Lactic Acid Bacteria and Preservation Technology of Fermented Starter

对1株经分离筛选得到的榨菜低盐腌制优良乳酸菌H17进行高密度培养性能研究,以细胞光密度(OD600)为指标,考察了高密度细胞培养的培养基条件、缓冲剂或中和剂对细胞生长的影响;由优化条件得到的培养物作发酵剂,比较了保藏条件对发酵活性的影响,筛选了冷冻保护剂及其合适的浓度。结果表明,选择基础培养基加5%蕃茄汁、培养温度30℃和Na2CO3为中和剂的条件下培养16h后乳酸菌活菌数最高达到1.14×1010CFU/mL;在生长稳定前期收获菌体,进行冷激处理,以5%蔗糖谷氨酸钠为冷冻保护剂,可提高乳酸菌冻干保存的存活率,达到64.1%。

In this paper, culture characteristics of high cell density were studied with a strain of Lactobacillus plantarum H17 used in low salinity pickled mustard tuber, which was obtained by isolating and screening. Effects of medium conditions, appropriate buffer solution or neutralizer on high cell density culture were investigated using the OD600 value as index. The cell activity of fermented starter obtained was compared under different preserving conditions as well as cryoprotectant and its concentration. The results showed that the maximum population of lactic acid bacteria reached 1. 14× 10^10 cfu/mL at the optimum culture condition of base medium by addition of 5% tomato juice, using 30% Na2CO3 as neutralizer at 30℃ for 20 hours. The survival rate of lactic acid bacteria was improved by harvesting pellet in the early stationary phase, treated with cold shock and addition of 5% sucrose and 5% MSG （monosodium glutamate）as frozen protector, and reached 64.1%.