杀线虫芽孢杆菌发酵条件优化及大孔树脂筛选

芽孢杆菌 SMrs28分离自草原毒草瑞香狼毒根际土壤,其代谢产物有明显的线虫触杀活性。为了确定该菌株的最优发酵条件及初步纯化活性成分的树脂类型,采用单因素试验对发酵条件进行优化,通过静态吸附试验对大孔树脂类型进行筛选。结果表明: SMrs28菌株的最优发酵条件为:以葡萄糖和酵母粉作为最佳碳源和氮源,发酵时间48 h,接种量10%,温度28 ℃,转速180 r·min^-1,150 mL的三角瓶装液量30 mL,初始pH 7.2。静态吸附试验表明,大孔吸附树脂D101对发酵液中活性成分的吸附和解吸效果显著优于XAD-4、HP20和AB-8,其解吸液的杀线虫活性明显提高。发酵条件的优化和大孔吸附树脂的筛选,明显提高了发酵液的杀线虫活性,为进一步分离纯化该菌株的活性成分奠定了基础,为微生物杀线虫剂的开发和应用提供了理论依据。

Optimization of the fermentation conditions of Bacillus nematodes and screening of macroporous adsorption resin

Bacillus sp. SMrs28, metabolites from which had significant nematicidal activity, was isolated from the rhizosphere soil of Stellera chamaejasme. To determine the optimal fermentation conditions of the strain and the resin type of preliminary purified active ingredient, fermentation conditions were optimized by single factor experiment, while the macroporous resin types were screened in a static adsorption experiment. The results showed that the optimal fermentation conditions of SMrs28 strain were as follows: glucose and yeast powder were the best carbon source and nitrogen source, fermentation for 48 h, inoculum volume of 10%, temperature at 28 ℃,a rotation speed of 180 r·min^-1, liquid volume of 30 mL in 150 mL triangular flask, and with an initial pH of 7.2. The static adsorption experiments showed that the adsorption and desorption of active ingre-dients in the fermentation broth by the macroporous adsorption resin D101 was significantly better than that of XAD-4, HP20 and AB-8, with the nematicidal activity of the desorption liquid being significantly improved. The nematicidal activity of fermentation broth was significantly improved by the optimization of fermentation conditions and the screening of optimal macroporous adsorption resins. These results laid a foundation for the further isolation and purification of active ingredients from SMrs28 strain, and provided theoretical basis for the development and utilization of microbial nematicides.