固定化乳酸乳球菌连续生产Nisin的研究

CONTINUOUS PRODUCTION OF NISIN BY CALCIUM ALGINATE- IMMOBILIZED LACTOCOCCUS LACTIS SUBSP. LACITS SM526

以海藻酸钙为材料 ,固定乳酸乳球菌 (Lactococcuslactissubsp .lactis)SM5 2 6 ,研究不同条件对Nisin合成的影响。结果表明 ,利用 2 %海藻酸钠在 1 0mmol LCaCl2 条件下 ,得到的固定化细胞颗粒稳定性较好 ,可维持 90h无破裂 ;在发酵过程中SYS3培养基中的无机盐成分尤其磷酸盐对固定化颗粒有破坏作用 ;用mSYS3培养基代替SYS3 ,通过 72h三批次循环的半连续培养 ,Nisin活性为 85 0IU mL ,无明显的细胞渗漏现象。连续化生产 70h ,Nisin活性达 1 1 5 0IU mL ,相当于游离细胞的发酵水平。

The attempts were made to produce nisin by immobilized cells of Lactococcus lactis subsp.lactis SM526 entrapped in calcium alginate beads. The results showed that the immobilized cell beads were intact for 90hr under 2% of calcium alginate in 10mmol/L CaCl 2 solution. The physical stability of beads was improved by removing phosphate, citrate and acetate salts supplied in SYS3 medium.Repeated-batch fermentation utilizing immobilized cells were performed in mSYS3 medium without agitation at 32℃, the concentration of nisin produced during the third cycles increased to 850 IU/mL, and the beads were still intact with little cell leakage. The immobilized beads were loaded into a sterilized glass column to continuous fermentation, nisin concentration increased to 1150 IU/mL, as high as that obtained in free-cell fermentation, and the high productivity was stable for up to 70h under a constant supplied of the fresh mSYS3 medium.