Degradation mechanism of aflatoxin B1 and aflatoxin G1 by salt tolerant Bacillus albus YUN5 isolated from ‘doenjang’, a traditional Korean food

• Published in: Food research international 2023-03, Vol.165, p.112479-112479, Article 112479
• Main Authors: Kumar, Vishal, Bahuguna, Ashutosh, Lee, Jong Suk, Sood, Ankur, Han, Sung Soo, Chun, Hyang Sook, Kim, Myunghee
• Format: Article
• Language: English
• Subjects: Aflatoxin; Aflatoxin B1; aflatoxin G1; Aflatoxins; Animals; Bacillus; Biodegradation; Doenjang; fermentation; food research; heat; Humans; Lactones; liquid chromatography; Liquid chromatography-mass spectrometry; Optimization; peptidase K; Republic of Korea; salt concentration; Salt tolerance; soybean paste; spectroscopy
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2023.112479

[Display omitted] •An aflatoxin degrading salt-tolerant bacteria B. albus was isolated from doenjang.•Extracellular substances were found responsible for aflatoxin degrading activity.•Aflatoxin B1 and G1 degrading substances were found non-proteinous nature.•Aflatoxin B1 and G1 degradation significantly affected by time, temperature and pH.•Aflatoxin B1 and aflatoxin G1 degradation pathways were proposed. Aflatoxins are the mycotoxins that contaminate food and feed and pose health hazards to humans and animals. Here, Bacillus albusYUN5 was isolated from doenjang (Korean fermented soybean paste) and examined for aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) degradation capabilities. The highest degradation of AFB1 (76.28 ± 0.15%) and AFG1 (98.98 ± 0.00%) was observed in the cell-free supernatant (CFS) ofB. albusYUN5, whereas negligible degradation was observed in intracellular fraction, viable cells, and cell debris. Furthermore, heat (100 °C) and proteinase K treated CFS possessed AFB1 and AFG1 degradation ability, suggesting that substances other than proteins or enzymes are responsible for the degradation. Optimal degradation of AFB1 and AFG1 by the CFS was achieved at 55 °C and 45 °C, respectively, and at pH 7–10 and salt concentration of 0–20%. Liquid chromatography–mass spectroscopy analysis of the degraded products revealed that either the difuran or lactone ring of AFB1 and lactone ring of AFG1 is the main target site by CFS of B. albus YUN5. A slightly better reduction of AFB1 and AFG1 was observed in doenjang treated with CFS and viable cells of B. albus YUN5 compared to those without CFS and B. albus YUN5 treated doenjang during one year of fermentation, suggesting the applicability of B. albus in real food.