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

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。

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.Plack-ett-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 concen-tration 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 indi-cates that it is possible to increase bacterial yield and reduce its costs using optimized growth medium.