索诺拉沙漠芽孢杆菌s262降解黄曲霉毒素B1发酵条件优化及活性物质初步分析

Optimization of fermentation conditions for degradation of aflatoxin B 1 by Bacillus sonorensis s262 and preliminary analysis of active substances

为探究索诺拉沙漠芽孢杆菌s262中降解黄曲霉毒素B1(Aflatoxin B1,AFB1)的活性物质,在单因素试验基础上,结合响应面法对菌株s262降解AFB1的发酵条件进行了优化,使用硫酸铵沉淀发酵上清液中的蛋白质,对粗酶液进行了质谱分析及酶活检测。结果表明:降解活性物质主要来自菌株的胞外代谢产物;最优发酵条件为种子液接种量6%、发酵时间48 h、发酵温度38℃;质谱检测得出的过氧化氢酶活性与AFB1降解率呈显著正相关(P<0.01)。推测过氧化氢酶为菌株s262发酵液降解AFB1的主要活性物质。

To investigate the active substances of aflatoxin B 1(AFB 1)degradation in Bacillus sonorensis s262,the fermentation conditions for AFB 1 degradation by strain s262 were optimized based on a single-factor test combined with response surface methodology.The proteins in the fermentation supernatant were precipitated using ammonium sulfate,and the crude enzyme solution obtained was subjected to mass spectrometry analysis and enzyme activity assay.The results showed that:the degradation active substances were mainly derived from the extracellular metabolites of the strains.The optimal fermentation conditions were 6% inoculum of seed solution,48 h fermentation time,and 38℃ fermentation temperature.The catalase activity derived from the mass spectrometry assay showed a significant positive correlation with the AFB 1 degradation rate(P<0.01).Therefore,it is hypothesized that catalase is the main active substance in the degradation of AFB 1 by the fermentation broth of strain s262.