玉米赤霉烯酮降解菌的筛选与鉴定

Isolation and Identification of Zearalenone-Degrading Bacterium

采用富集驯化的方法从猪粪便中分离出一株能够高效降解玉米赤霉烯酮(zearalenone,ZEN)的菌株,命名为ZJ-2019-1.通过16S rDNA序列分析方法对其进行了鉴定,研究了反应时间、培养基初始pH、温度、毒素浓度等因素对ZJ-2019-1降解ZEN的影响,同时对该菌株清除ZEN的机理进行了初步探索.结果表明:ZJ-2019-1为枯草芽孢杆菌(Bacillus subtilis);该菌株在48 h内能将LB培养基中初始浓度为10mg/L的ZEN去除99.7%;该菌株降解ZEN的最适温度为37℃,当反应温度低于27℃时,该菌株对ZEN的清除率明显降低;当培养基初始pH5.0~9.0时,ZJ-2019-1对ZEN的清除率能达到88%以上,其中初始pH7.0为降解反应的最适pH;当初始ZEN浓度在20 mg/L以内时,ZJ-2019-1对ZEN的清除率都在95%以上;ZJ-2019-1对ZEN的清除作用主要源于胞外酶的活性.

In this study,a pure culture of strain ZJ-2019-1,identified as Bacillus subtilis based on 16S rDNA gene sequence analysis methods,was isolated from pig feces by enrichment and domestication culture and showed to be effective in degrading zearalenone(ZEN).The effects of factors,including reaction time,initial medium pH,temperature and toxin concentration,on the elimination of ZEN by ZJ-2019-1 were investigated.Meanwhile,the mechanism of ZEN elimination by ZJ-2019-1 was also preliminarily explored.The results were as follows.10 mg/L of ZEN in LB broth was 99.7%removed within 48 hours by ZJ-2019-1.The optimal degradation temperature of ZEN was 37℃,and when the reaction temperature was below 27℃,the removal rate of ZEN was significantly reduced.When the initial pH of the medium was 5.0~9.0,the degradation rates of ZEN by ZJ-2019-1 were all over 88%,and the initial pH 7 was the optimal pH for degradation reaction.While the initial ZEN concentration was less than 20mg/L,the degradation rate of ZEN by ZJ-2019-1 were all above 95%.The removal of ZEN by ZJ-2019-1 was mainly due to its extracellular enzyme activity.