AUTHOR=Wang Lingling , Wu Jun , Liu Zhiwen , Shi Yutao , Liu Jinqiu , Xu Xiaofan , Hao Shuxian , Mu Peiqiang , Deng Fengru , Deng Yiqun 

TITLE=Aflatoxin B1 Degradation and Detoxification by Escherichia coli CG1061 Isolated From Chicken Cecum

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 9 - 2018

YEAR=2019

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2018.01548

DOI=10.3389/fphar.2018.01548

ISSN=1663-9812

ABSTRACT=Aflatoxin B1 (AFB1) is one of the most hazardous mycotoxins contamination in
19 food and feed products, which leads to hepatocellular carcinoma in humans and
20 animals. In the present study, we isolated and characterized an AFB1 degrading
21 bacteria CG1061 from chicken cecum, exhibited an 93.7% AFB1 degradation rate by
22 HPLC. 16S rRNA gene sequence analysis and a multiplex PCR experiment
23 demonstrated that CG1061 was a non-pathogenic Escherichia coli. The culture
24 supernatant of E. coli CG1061 showed an 61.8% degradation rate, whereas the
25 degradation rates produced by the intracellular extracts was only 17.6%, indicating
26 that the active component was constitutively secreted into the extracellular space. The
27 degradation rate decreased from 61.8% to 37.5% when the culture supernatant was
28 treated with 1 mg/mL proteinase K, and remained 51.3% when that treated with
29 100 ℃ for 20 min. We postulated that AFB1 degradation was mediated by
30 heat-resistant proteins. The content of AFB1 decreased rapidly when it was incubated
31 with the culture supernatant during the first 24 h. The optimal incubation pH and
32 temperature were pH 8.5 and 55 ℃ respectively. According to the UPLC Q-TOF MS
33 analysis, AFB1 was bio-transformed to the product C16H14O5 and other metabolites.
34 Based on the results of in vitro experiments on chicken hepatocellular carcinoma
35 (LMH) cells and in vivo experiments on mice, we confirmed that CG1061-degraded
36 AFB1 are less toxic than the standard AFB1. E. coli CG1061 isolated from healthy
37 chicken cerum is more likely to colonize the animal gut, which might be an excellent
38 candidate for the detoxification of AFB1 in food and feed industry