一株具有乙酰胆碱酯酶抑制活性的牡蛎内生细菌筛选鉴定及发酵条件优化

Isolation and Identification of an Endophytic Bacterium with Acetylcholinesterase Inhibitory Activity Derived from Oyster and the Optimization of Fermentation Conditions

基于内共生理论,从牡蛎体内分离内生细菌,采用改良Ellman法对获得的菌株进行乙酰胆碱酯酶抑制活性的筛选,对获得的活性菌株采用生理生化试验结合16SrDNA序列分析的方法鉴定其属种,并通过单因素试验和正交试验对该菌株进行发酵条件的优化。结果表明:从牡蛎中共分离出8株内生细菌,其中具有乙酰胆碱酯酶抑制活性的只有1株,该菌株经鉴定属于枯草芽孢杆菌(Bacillus subtilis)。其发酵的最佳条件为以葡萄糖为碳源,蛋白胨为氮源,培养温度37℃,发酵时间78h,发酵培养基初始pH=7.8,接种量11.0%,摇床转速140r/min。该发酵条件下得到的发酵液乙酰胆碱酯酶抑制率为22.4%,比未优化前提高了3.3倍。

Based on the symbiosis theory,endophytic bacteria were isolated from oysters.Screening of ace-tylcholinesterase inhibitory activity of the isolated bacteria by the modified Ellman method,physiological and biochemical tests combined with 16S rDNA sequence analysis were used for identification of the spe-cies.Besides,fermentation conditions were optimized through single factor tests and orthogonal tests. The results show that there were 8 strains endophytic bacteria separated from oyster and only one of them had the AChE inhibitory activity,which was identified as Bacillus subtilis.The optimum condition for the fermentation is glucose as carbon source,peptone as nitrogen source,pH=7.8,11% inoculation amount, rotation speed 140 r/min at 37 ℃ for 78 h.Under this condition,the inhibition rate was 22.4%,which in-creased to 3.3 times as before.