贝莱斯芽孢杆菌N4菌株摇瓶发酵条件的响应面法优化OA

[Objective]This research aims to optimize the fermentation medium formulations and shake-flask fermentation conditions of the biocontrol bacterium Bacillus velezensis N4,which exhibits significant inhibi-tory activity against Fusarium tobaccum LH156101,to provide a reference for the application of B.velezensis N4 in controlling Fusarium wilt disease of tobacco.[Method]Single-factor experiments and Box-Behnken design were carried out to analyze the effects of different fermentation medium formulations(carbon sources,nitrogen sources and inorganic salts)and environmental conditions(temperature,initial pH,rotationl speed,inoculation volume,liquid volume and fermentation time)on the bacterial biomass of B.velezensis N4 and N4 strain inhibi-tory activity against F.tobaccum LH156101,to determine the optimal liquid fermentation medium formulations and environmental conditions for the B.velezensis N4.[Result]The fermentation medium components and en-vironmental conditions significantly affected the bacterial biomass accumulation of B.velezensis N4 and N4 strain inhibitory activity against F.tobaccum.The optimal carbon source,nitrogen source,and inorganic salt in the fer-mentation medium were yeast extract(optimal concentration 20 g/L),soybean peptone(15 g/L)and NaCl(3.0 g/L).The optimal shake-flask fermentation conditions were as follows:initial pH of 6.0,liquid volume of 60 mL,inoculum amount of 1%,fermentation temperature of 30℃,rotationl speed of 180 r/min,and fermenta-tion time of 24 h.Under the above-mentioned conditions,bacteria cell biomass reached 2.39×1010 CFU/mL,representing a 13.66 times increase in bacterial biomass compared with that before optimization,with an inhibi-tory activity rate of 78.60%.[Conclusion]The optimal fermentation medium formulations and shake-flask fer-mentation conditions for Bacillus velezensis N4 were established.This study provides technical support for the development and utilization of B.velezensis N4 and offers a scientific basis for the effective control of Fusarium wilt disease of tobacco.