红树林植物促生菌SZ7-1 菌株的培养基优化

Optimization of growth medium for a PGPR strain (SZ7-1) from mangrove rhizosphere

摘要:

采用响应面分析法对红树林植物促生菌SZ7-1 菌株发酵培养基进行了优化。首先利用Plackett-Burman (PB)设计对影响SZ7-1 生长的11 个营养因素进行评价, 并筛选出显著影响因子:玉米糖浆、酵母膏和K₂HPO₄; 其次用最陡爬坡实验逼近以上三因素最优水平; 最后采用响应面法对该3 个显著因素的最佳水平范围进行研究, 得到的最佳浓度为: 玉米浆28 g/L、酵母膏14 g/L和K₂HPO₄ 2.2 g/L。在此条件下, 培养20 h 后SZ7-1 菌数达到2.6×10¹⁰ CFU/mL, 与优化前基础培养基、LB 和牛肉膏蛋白胨培养基中生长的菌数相比, 分别提高了12.4、2.4 和5.5 倍。

关键词:SZ7-1, Plackett-Burman 设计, Box-Behnken 设计, Minitab 软件, 响应面法

Abstract:

A plant growth-promoting rhizobacteria (PGPR) strain, SZ7-1, was obtained from mangrove rhizosphere and tested previously for potential applications. To develop an economical and practical fermentation medium for the growth of SZ7-1, response surface method was used in this study. Plackett– Burman factorial design was used to examine the significance of 11 different media on the growth of SZ7-1. Experimental result demonstrated that media consisting of corn syrup, yeast extract and K₂HPO₄ significantly improved the growth process. The effect of different combinations of the three nutrients on the growth of SZ7-1 were further explored in a Box-Behnken design. The optimal concentration of each nutrient for maximum growth were corn syrup 28 g/L, yeast extract14 g/L and K₂HPO₄ 2.2 g/L. The optimized medium enhanced the growth of SZ7-1 by 12.4, 2.4 and 5.5 times more than the original medium, LB and cow meat extract protein peptone medium, respectively. This research indicates that it is possible to increase bacterial yield and reduce its costs using optimized growth medium.

Key words:SZ7-1, Plackett–Burman design, Box-Behnken design, Minitab software, Response surface methodology