解淀粉芽孢杆菌HRH317菌株抗菌肽发酵条件优化及其抑菌活性研究

Optimization of fermentation conditions and antibacterial activity of antimicrobial peptides from Bacillus amylolytica HRH317 strain

中文关键词:  解淀粉芽孢杆菌  抗菌肽  抗菌活性  最小抑菌浓度

英文关键词:Bacillus amylolytica  antimicrobial peptide  antimicrobial activity  minimum inhibitory concentration

中文摘要:

      目的 优化解淀粉芽孢杆菌HRH317菌株产抗菌肽的发酵条件并探讨其抑菌活性。方法 采用单因素试验和响应面法, 以抑菌圈直径为指标, 对解淀粉芽孢杆菌HRH317菌株产抗菌肽的发酵条件进行优化; 采用牛津杯法测定该抗菌肽的抑菌谱活性并通过双缩脲法研究其最小抑菌浓度(minimum inhibitory concentration, MIC)。结果 解淀粉芽孢杆菌HRH317菌株产抗菌肽的最佳发酵条件为: pH为7.5, 装液量为50 mL, 接种量3%, 培养时间13 h、温度38.5 ℃、转速145 r/min, 抗菌肽含量(50.53±0.37) μg/mL。在此条件下抗菌肽的抑菌圈直径达15.97 mm。且针对9种指示菌的抑菌谱结果表明, 抗菌肽对枯草芽孢杆菌、金黄色葡萄球菌的MIC为3.45 μg/mL, 大肠杆菌、白地霉、巴氏醋酸杆菌MIC为6.90 μg/mL, 禾谷镰孢菌、黄曲霉、假丝酵母MIC为55.20 μg/mL, 红酵母MIC为110.40 μg/mL。结论 发酵时间、转速及接种量是影响抗菌肽产量的主要因素。该抗菌肽具有广谱抗菌性, 尤其对枯草芽孢杆菌、金黄色葡萄球菌抑制效果最好, 其次是霉菌、酵母菌。

英文摘要:

      Objective To optimize the fermentation conditions of antibacterial peptide produced by Bacillus amylolytica HRH317 and study its antimicrobial activity. Methods The fermentation conditions for the production of antimicrobial peptides by Bacillus amylolytica HRH317 strain with the diameter of the inhibition zone as an indicator were optimized by the single factor experiment and response surface method. The antimicrobial activity of the peptide was determined by Oxford Cup method and its minimum inhibitory concentration (MIC) was studied by biuret method. Results The optimal fermentation conditions for producing antimicrobial peptides by Bacillus amylolytica HRH317 were as follows: pH was 7.5, the filling volume was 50 mL, the inoculation was 3%, the culture time was 13 h, the temperature was 38.5℃, the rotation speed was 145 r/min, and the antimicrobial peptide content was (50.53±0.37) μg/mL. Under this condition, the inhibition zone diameter of the antimicrobial peptide was 15.97 mm. The results of antibacterial spectrum against 9 kinds of indicator bacteria showed that the MIC of antimicrobial peptides against Bacillus subtilis and Staphylococcus aureus was 3.45 μg/mL, against Escherichia coli, Geotrichum and Acetobacter pasteurella was 6.90 μg/mL, against Fusarium graminearum, Aspergillus flavus and Candida was 55.20 μg/mL, and the MIC of Rhodotorula was 110.40 μg/mL. Conclusion Fermentation time, rotation speed and inoculum amount were the main factors affecting the yield of antimicrobial peptides. Moreover, the antimicrobial peptide has broad-spectrum antibacterial activity, especially for Bacillus subtilis and Staphylococcus aureus, followed by mold and yeast.