Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium#

International Journal of Molecular Sciences

Shu Guan¹  Cheng Ji¹  Ting Zhou²  Junxia Li³  Qiugang Ma¹ 

[1] National Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100094, China. E-Mails:;Guelph Food Research Center, Agriculture and Agri-Food Canada, Guelph N1G 5C9, Canada. E-Mail:;College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. E-Mail:

关键词: aflatoxin B₁;    degradation;    culture supernatant;    Stenotrophomonas maltophilia;   

DOI  :  10.3390/ijms9081489

来源: mdpi

【 摘 要 】

Aflatoxin B₁ (AFB₁) is one of the most harmful mycotoxins in animal production and food industry. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 65 samples were screened from various sources with vast microbial populations using a newly developed medium containing coumarin as the sole carbon source. Twenty five single-colony bacterial isolates showing AFB₁ reduction activity in a liquid culture medium were selected from the screen. Isolate 35-3, obtained from tapir feces and identified to be Stenotrophomonas maltophilia, reduced AFB₁ by 82.5% after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of isolate 35-3 was able to degrade AFB₁ effectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB₁ degradation by the culture supernatant were investigated. Activity was reduced to 60.8% and 63.5% at 20 °C and 30 °C, respectively, from 78.7% at 37 °C. The highest degradation rate was 84.8% at pH 8 and the lowest was only 14.3% at pH 4.0. Ions Mg²⁺ and Cu²⁺ were activators for AFB₁ degradation, however ion Zn²⁺ was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the degradation activity of the culture supernatant. The results indicated that the degradation of AFB₁ by S. maltophilia 35-3 was enzymatic and could have a great potential in industrial applications.

【 授权许可】

CC BY   
© 2008 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).