Identification of a Novel Bacillus velezensis IS-6 Nudix Hydrolase Nh-9 Involved in Ochratoxin A Detoxification by Transcriptomic Profiling and Functional Verification

文献类型： 外文期刊

第一作者： Jahan, Israt

作者： Jahan, Israt;Tai, Bowen;Ma, Junning;Hussain, Sarfaraz;Du, Haolan;Guo, Ling;Wang, Gang;Adegoke, Tosin Victor;Ma, Longxue;Xing, Fuguo

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关键词： ochratoxin A; Bacillus velezensis; LC-MS; MSmetabolites; transcriptomics; gene expression; Nudix hydrolase

期刊名称：JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY （ 影响因子：6.1； 五年影响因子：6.3 ）

ISSN： 0021-8561

年卷期： 2023 年 71 卷 26 期

页码：

收录情况： SCI

摘要： Contamination of foods and feeds with Ochratoxin A (OTA)is a globalproblem, and its detoxification is challenging. In this study, Bacillus velezensis IS-6 culture isolate supernatantdegraded 1.5 g/mL OTA by 89% after 24 h of incubation at 37 & DEG;C,whereas viable cells and intra-cell extracts were less effective.The OTA degradation by B. velezensis IS-6 was an enzymatic process mediated by the culture supernatant.The degradation activity was optimal at 37 & DEG;C and pH 7.0, andFe(2+) and Cu2+ ions enhanced the OTA degradation.The LC-MS/MS analysis confirmed that structure of OTA was modified,resulting in the production of OT & alpha; that was less toxic thanOTA. The transcriptomic analysis of B. velezensis IS-6 showed that 38 differentially expressed genes (DEGs) were significantlyup-regulated, and 24 DEGs were down-regulated after treatment withOTA. A novel OTA degradation enzyme Nudix hydrolase Nh-9 was successfullycloned and characterized from the up-regulated genes. The recombinantNh-9 enzyme was overexpressed in Escherichia coli BL21 and purified by affinity chromatography, exhibiting 68% degradationactivity against 1.0 & mu;g/mL OTA at 37 & DEG;C in 24 h. The degradedproduct by the Nh-9 enzyme was identified as the less toxic OT & alpha;by LC-MS/MS. According to the findings, it can be inferredthat Nh-9 is the main OTA-degrading enzyme in B. velezensis IS-6. Furthermore, OTA may be co-degraded by Nh-9, carboxylesterase,signal peptidase, and other degrading agents that are yet to be discoveredin this strain.

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