外源氨基酸对侧孢短芽孢杆菌S62-9产Brevilaterin的影响

为探究添加外源氨基酸对侧孢短芽孢杆菌S62-9(Brevibacillus laterosporus S62-9, BL)分泌抗菌肽Brevilaterin的影响,以BL发酵液的抗菌活性和Brevilaterin的组分变化为指标,分别采用琼脂扩散法和高效液相色谱法进行了分析。结果表明:添加L-缬氨酸、L-甲硫氨酸和2-氧代-3-甲基丁酸均能提高发酵液抗菌活性,抑菌直径最高可增加18.08%。添加外源氨基酸还能改变Brevilaterin的组分构成。添加L-甲硫氨酸后发酵液中只有抗菌肽组分Brevilaterin B和C,且二者间的相对比例发生反转；而添加L-缬氨酸或2-氧代-3-甲基丁酸还能促进BL分泌多种新组分。添加外源氨基酸能有效提高发酵液抗菌活性并改变抗菌肽的组分构成,研究结果旨在为人工调控微生物合成新型、高效的抗菌肽奠定一定的理论基础。

Effects of Exogenous Amino Acids on Production of Brevilaterin from Brevibacillus laterosporus S62-9

To explore the effect of addition of exogenous amino acids on Brevibacillus laterosporus S62-9 (BL) secreted Brevilaterin, the antibacterial activity of BL fermentation broth and the composition change of Brevilaterin were analyzed by agar diffusion method and high performance liquid chromatography, respectively. The results showed that the addition of L-valine, L-methionine and 2-oxo-3-methyl-butyric acid could increase the antibacterial activity of the fermentation broth, and the maximum antibacterial diameter could increase by 18.08%. Furthermore, the addition of exogenous amino acids could also change the components of Brevilaterin. The addition of L-methionine could induce BL only to secrete Brevilaterin B and C, and the relative ratio between the two was reversed. The addition of L-valine or 2-oxygen-3-methyl-butyric acid also promoted BL to secrete a variety of new components. In conclusion, adding exogenous amino acids could effectively improve the antibacterial activity of the fermentation broth and even change the components of antimicrobial peptides, which might provide a theoretical foundation for the artificial regulation of microbial synthesis of novel and efficient antimicrobial peptides.