Isolation, Characterization, and Biopreservation of Lactobacillus brevis DN-1 to Inhibit Mold and Remove Aflatoxin B1 in Peanut and Sunflower Cakes

Abstract

Aflatoxin B1 (AFB1) is the most toxic mycotoxin and is widespread in moldy feed. The use of biological removal methods to reduce AFB1 has become a research hotspot. This study aimed to isolate lactic acid bacteria (LAB) capable of removing AFB1 from moldy feeds and assessed the removal capacity under various environmental conditions. A strain named Lactobacillus brevis DN-1 was isolated from feed samples and showed 71.38% AFB1 percent removal. Furthermore, DN-1 showed good antifungal activity against Aspergillus flavus BNCC336156 and Aspergillus parasiticus BNCC335939. The optimum growth temperature and pH of DN-1 were 37 °C and 6.0, respectively, and DN-1 grew well in the concentration range of 0–20 µg/L AFB1. Under a temperature of 20–40 °C, pH of 3.0–9.0, and anaerobic conditions, the percent removal of AFB1 was more than 60%. An analysis of the different components of DN-1 showed that cell wall adsorption was the main removal method and suggested the pathway for AFB1 removal by LAB. In addition, strain DN-1 was used as a biological preservative in artificially contaminated peanut and sunflower cakes, which significantly inhibited the growth of mold and production of AFB1. In brief, this study highlights the potential use of DN-1 as a preventive agent against aflatoxicosis via strong removal capability in the application of fermented feed or food.