枯草芽胞杆菌B006产表面活性素的培养条件优化

Optimization of Culture Conditions for the Enhancement of Surfactin Production from Bacillus substilis B006

芽胞杆菌产生的环脂肽类生物表面活性素surfactin具有重要抗菌、促进生物膜形成等功能,其含量和同系物组分构成影响其功能。为了提高芽胞杆菌B006产生表面活性素的产量,通过单因素实验和正交实验,测定了碳源、氮源和无机盐等营养物质及接种量、培养时间、装液量和初始pH值对芽胞杆菌B006摇瓶发酵产生表面活性素的影响;采用排油圈法测定发酵液中表面活性素的产量,采用HPLC-MS方法比较培养基优化前后surfactin的产量和组分含量。结果表明,适合芽胞杆菌B006摇瓶发酵产生表面活性素的培养基组成为:牛肉膏10 g/L、玉米粉15 g/L、硝酸铵3 g/L和氯化钠3 g/L;适合的培养条件为:初始pH值7.0、接种量10%、装液量60 m L/500 m L,发酵周期64 h。优化后surfactin的产量约为314.73 mg/L,比优化前提高了74.88%;surfactin各组分比例发生改变,其中C16和C17组分的含量明显提高,为优化前相应组分含量的1.64和8.34倍。优化的培养基组分和培养条件可明显提高芽胞杆菌B006菌株产生surfactin的产量,改变surfactin同系物组分的构成,为利用芽胞杆菌B006进行高活性表面活性素的工业生产和代谢调控研究奠定了基础。

Bio-surfactin produced by Bacillus spp. is one kind of cyclic lipopetide with important antibiotic and biofilm-promoting functions, and the amount and component constitution affect its functions. In order to improve its production from Bacillus strain B006, the liquid culture medium and fermentation conditions were optimized by single-factor experiment and orthogonal experiment, and the effects of carbon source, nitrogen source, inorganic salts, and other nutrients, as well as inoculation, incubation time, liquid volume and initial pH value on surfactin production of Bacillus B006 in shake flask were investigated. The surfactin amount in fermentation broth was determined by the oil dispersing activity in the optimal tests, and its amount as well as component constitution were finally analyzed and determined by HPLC-MS method. Results showed that, the optimized culture mediums of surfactin production were as follows ： beef extract 10 g/L, corn flour 15 g/L, NH4NO3 3 g/L, and NaCl 3 g/L. The optimized fermentation conditions for surfactin production in shaking flask were as follows ： initial pH7.0, the inoculation ratio 10%, volume in shake flask 60 mL/500 mL, and culture time 64 h. Under the optimal culture medium and fermentation conditions, the surfactin amount reached 314.73 mg/L, with an improvement of 74.88%, and the amount of surfactin components C16 and C17 increased obviously, raised by 1.64 and 8.34 times, in comparison with no optimization. In a conclusion, under optimized medium components and culture conditions, the surfactin production from Bacillus strain B006 is improved and its component constitution change. All the above results lay a foundation for surfactin production in large scale and further research in metabolic and regulation of surfactin produced by strain B006.