Probiotic characteristics and zearalenone-removal ability of a Bacillus licheniformis strain

Zearalenone (ZEN) is a mycotoxin produced by Fusarium species, which is one of the main animal feed contaminants causing reproductive disorders in livestock. The aim of this study was to evaluate the probiotic characteristics and ZEN removal ability of a Bacillus licheniformis strain CK1. The probiotic properties, including acidic tolerance, bile salt tolerance, adherence capability, and anti-pathogenic activities of CK1 were evaluated. CK1 survived after incubation at pH 2.0 or 3.0 for 3 h, grew well in LB broth containing 0.3% oxgall, possessed adherence capability to Caco-2 cells, and inhibited the growth of Escherichia coli O157:H7 and Listeria monocytogenes. The ZEN removal ability of CK1 was compared with a mineral mycotoxin-adsorbing agent, hydrated sodium calcium aluminosilicate (HSCAS), and a well-characterized biological mycotoxin-adsorbing agent, Lactobacillus rhamnosus GG (LGG). At 37°C in phosphate-buffered saline (PBS, pH 7.0) containing 5 μg mL-1 of ZEN, the ZEN removal percentage of CK1 was 73.0%, which was significantly higher than that of HSCAS and LGG (45.9% and 48.4%, respectively). In the pH range of 2.5-8.0, CK1 removed up to 65% of ZEN. At temperatures between 4 and 42°C, CK1 removed more than 75% of ZEN. In the adsorption stability analysis, the amounts of ZEN removed by CK1 was over 30% even after five consecutive rounds of washing procedures. These findings demonstrated that CK1 displayed probiotic characteristics and removed ZEN effectively. Therefore, CK1 has a great potential for the development of feed additive to remove ZEN.