应用数学统计法优化副干酪乳杆菌HD1.7固定化细胞制备和产细菌素发酵

Statistical methods to optimize immobilization and bacteriocin production by Lactobacillus paracasei HD1.7

摘要:

摘要：【目的】应用数学统计法对副干酪乳杆菌HD1.7的固定细胞制备和发酵条件进行优化，以提高细菌素产量。【方法】用26?2部分因子分析法筛选对细菌素产量影响显著的因子，发现海藻酸钠浓度、接种量和发酵时间对细菌素的产生影响显著。利用最陡爬坡法逼近最大响应区域。用Box-Behnken设计确定最佳海藻酸钠浓度、接种量和发酵时间，并进行分批重复发酵。【结果】固定化生产细菌素的最佳条件是海藻酸钠浓度2.8%、CaCl2浓度5%、固定化时间4 h、菌体包埋量1/20、发酵时间63 h和固定化细胞的接种量8.2%，在此基础上用固定化细胞进行分批重复发酵，每批细菌素的发酵周期为24 h，产量为游离发酵的70%，比游离细胞发酵周期缩短1/2。【结论】通过对固定化细胞制备和发酵条件的优化，固定化细胞在327 h的分批重复发酵中细菌素的总体产量比游离细胞提高了19%，发酵液中无明显细胞渗漏现象且实现了细胞的重复利用，为细菌素的进一步研究和最终提取奠定了基础。

Abstract:

Abstract: [Objective] To enhance bacteriocin production by Lactobacillus paracasei HD1.7 immobilized with calcium alginate gel by statistical methods. [Methods] A 26?2 two-level fractional factorial design was employed first where 6 variables were studied for their influence on bacteriocin production. The concentration of sodium alginate, inoculation volume and culture time were the most significant variables to improve bacteriocin production. The greatest response area was estimated by the design of steepest ascent approach. A three-level Box–Behnken factorial design was employed for maximizing the bacteriocin production and the number of cell cycle. The repeated batch fermentation using immobilized cells was done. [Results] The optimal condition for bacteriocin production and the number of cell cycle was with sodium alginate 2.8%, CaCl2 5%, immibilization time 4 h, the density of entrapped cells 1/20, culture time 63 h and inoculation volume 8.2%. The period of fermentation was 24 h of a batch fermentation after 63 h and bacteriocin production was 70% of free-cell fermentation. [Conclusion] After optimizing, the total production of bacteriocin was increased by 19% using the batch fermentation during 327 hours, the beads were intact with little cell leakage and repeatedly used, which laid foundation for the high study of bacteriocin and finally extracted.