Screening and characterization of a salt-tolerant aflatoxin B1-degrading strain isolated from Doubanjiang, a Chinese typical red pepper paste

Abstract

Aflatoxin B 1 (AFB 1 ) is a carcinogenic mycotoxin present in many foods, posing a serious human health problem. Oriental high-salt fermented foods are highly susceptible to AFB 1 contamination due to their production process and condition. Therefore, it is necessary to isolate microbial resources that can remove AFB 1 in a high-salt condition. In the current study, forty-nine salt-tolerant microorganisms with the ability to remove AFB 1 were isolated from Doubanjiang, a Chinese typical high-salt red pepper paste. Among them, Bacillus velezensis AD8 had the highest removal rate of AFB 1 . The AFB 1 removal activity of B. velezensis AD8 was mainly attributed to culture supernatant, and it was sensitive to sodium dodecyl sulfate (SDS) or/and proteinase-K treatment, which indicated that extracellular enzyme contributed to the degradation of AFB 1 . The optimal incubation time, pH value and NaCl concentration of the initial medium for degradation of AFB 1 by the B. velezensis AD8 were investigated. In addition, the AFB 1 concentration had no significant effect on degradation activity. The addition of nitrogen source, Mg 2+ and Mn 2+ stimulated degradation rate, whereas addition of carbon source, Zn 2+ and Fe 2+ inhibited degradation. Thus, B. velezensis AD8 might be a potential candidate to degrade AFB 1 in high-salt food matrices.

Screening and identification of an aflatoxin B1-degrading strain from the Qinghai-Tibet Plateau and biodegradation products analysis

“…Among the Bacillus Spp. with the highest reported degradation efficiency, including B. amyloliquefaciens B10 ( Xiong et al, 2022 ), B. amyloliquefaciens WF2020 ( Chen et al, 2022 ), B. velezensis AD8 ( Zhao et al, 2022 ), B. albus YUN5 ( Kumar et al, 2023 ), B. subtilis JSW-1 ( Xia et al, 2017 ), and B. licheniformis CFR1 ( Rao et al, 2017 ), none achieved efficiency exceeding 90% in previous studies. The utilization of B. amyloliquefaciens YUAD7 held the promise of significant time and cost reductions, making this process more effective.…”

Biosynthetic Gene Clusters in Sequenced Genomes of Four Contrasting Rhizobacteria in Phytopathogen Inhibition and Interaction with Capsicum annuum Roots

“…This result is not unusual given that these strains were isolated from spatially distant origins and had to adapt to very different habitat conditions. JS25R is from a Jiangsu province in China, GFP-2 was isolated from the intestine of Chiloscyllium plagiosum (Whitespotted bamboo shark) at the Zhejiang Sci-Tech University in China ( 18 ), and AD8 was isolated from a typical high-salt red pepper paste in China ( 19 ), while the 2A-2B strain originates from rhizosphere in the north central part of Mexico.…”