一株降解赭曲霉素A的新颖米曲霉菌株筛选鉴定及其产酶优化

SCREENING AND IDENTIFICATION OF A NOVEL ASPERGILLUS ORYZAE STRAIN DEGRADING OTA AND OPTIMIZATION OF THE FERMENTATION CONDITIONS

赭曲霉毒素A(OTA)是食品中常见的一种真菌毒素,如何有效清除OTA污染是提升食品安全品质的重要手段。目前OTA降解方式中生物降解是最具应用前景的研究方向。而生物降解研究中具有自主知识产权的高效安全降解菌株仍是稀缺资源。从土壤中筛选出一株OTA降解率达75%且鉴定为食品发酵生产中常用的米曲霉菌株M30011,随后对其降解OTA条件进行优化研究。经单因素分析选取其中影响显著的初始p H、培养温度和接种量3个因素进行响应面分析,得到最优降解条件。优化后该菌对OTA降解率达94%,产酶周期由8 d缩短至3 d,缩短62.5%。该菌本身应用安全性高且优化后具有降解率高、降解周期短等特点,研究结果为该菌在食品发酵领域采用生物降解方式消除OTA污染提供了技术基础。

Ochratoxin A （OTA） is a common mycotoxin found in food, and how to effectively remove the OTA contamination is an important way to improve food safety and quality. The biodegradation of OTA is the most promising research direction at present. However, the highly efficient and safe degradation strains with independent intellectual property fights are still scarce resources. Strain M30011 identified as Aspergillus oryzcle, commonly used in food microorganism fermentation, which had 75% degradation rate to OTA, was isolated from soil in this study and the fermentation conditions for degrading OTA was also optimized. Three significant effect factors of initial pH, culture temperature and inoculation amount were selected base on the single factor analysis, and the optimal conditions of degrading OTA were obtained by response surface analysis. After optimization, the degradation rate of OTA was 94% and the cycle of degrading OTA was shortened from 8 days to 3 days, shortened by 62.5%. The strain M30011 had high safety, high degradation rate and short degradation cycle. The present study will provide research foundation for the further application ofAspergillus oryzae strain on eliminating OTA pollution in the field of food fermentation.