贝莱斯芽孢杆菌FJ17-4发酵培养基和发酵条件优化

Optimization of Bacillus velezensis FJ17-4 Fermentation

【目的】贝莱斯芽孢杆菌FJ17-4对许多病原菌具有较强的抑制作用,为提高其生防作用,开展FJ17-4发酵技术研究。【方法】以发酵液的OD^(600)值为评估指标,采用单因素和正交试验方法对发酵培养基和发酵条件进行筛选和优化,获得最佳发酵培养基和发酵条件后,进一步对优化后发酵液的菌体数、病原菌抑制率和室内盆栽防治效果进行测定和分析。【结果】菌株FJ17-4的最佳培养基配方为黄豆粉12.5 g·L^(-1)、玉米粉5.0 g·L^(-1)、K^(2)HPO^(4)12.5g·L^(-1),最佳发酵条件为:初始pH 7.0,培养温度30℃,装液量20%(50 mL/250 mL),接种量12.5%,转速180r·min-1,发酵培养时间40 h。优化后发酵液的OD^(600)值和菌体数量分别为1.52×10^(10)、1.03×10^(10)cfu·mL^(-1),比优化前分别提高了25.62%和21.95%。50倍优化发酵液对病原菌菌丝生长抑制率和室内盆栽防治效果分别为42.35%和72.14%,比优化前分别提高了56.38%和13.46%。【结论】优化后发酵培养基和发酵条件有效提高菌株FJ17-4的发酵效果,降低了发酵成本,研究结果为贝莱斯芽孢杆菌FJ17-4的开发和工业化生产及应用提供了理论依据。

【Objective】Fermentation of Bacillus velezensis FJ17-4 known with a high inhibitory activity against several pathogens was optimized for potential application as a biocontrol agent.【Methods】Spectrometric measurement at OD^(600)of the fermentation broth was used as the index for evaluation.Culture medium and conditions were optimized by single factor and orthogonal experiments.Bacterial quantity,pathogenic inhibition,and indoor potted control effect of the optimized fermentation product were determined.【Results】The optimized FJ17-4 fermentation used a medium that consisted of 12.5 g·L^(-1)soybean meal,5.0 g·L^(-1)corn flour,and 12.5 g·L^(-1)potassium dihydrogen phosphate at an initial pH of 7.0 to ferment a liquid loading(medium volume)of 50 mL with an inoculum size of 12.5%for 40 h at 30℃in a 250 mL flask that rotated at a constant speed of 180 r·min-1.The OD^(600)of the optimized fermentation broth was 1.52 representing a cell load of 1.03×10^(10)cfu·mL^(-1),which were 25.62%and 21.95%,respectively,higher than those prior to the optimization.The inhibition rate on the mycelial growth of Fusarium oxysporum f.sp.cucumerinum and the indoor potted control on cucumber fusarium wilt of the 50×optimized fermentation broth were 42.35%and 72.14%,representing 56.38%and 13.46%increases,respectively,over the original.【Conclusion】The FJ17-4 fermentation was significantly improved by the optimization.An operational cost reduction was also achieved.