In vitro evaluation of the ability of Lacticaseibacillus rhamnosus and Saccharomyces cerevisiae strains to bind fumonisins in buffer solution.

This in vitro study evaluated the ability of commercial Lacticaseibacillus rhamnosus and Saccharomyces cerevisiae strains to remove fumonisins B1 (FB1) and B2 (FB2) at pH 3.0 and 7.0. Two L. rhamnosus strains (LR40 and LR100) and one strain of S. cerevisiae (SC1) commercially available in Italy were cultivated under appropriate conditions until reaching cell concentrations of 109 and 108 cells/mL, respectively. Strains of L. rhamnosus (LRB) and S. cerevisiae (SC2), each containing 1.0 × 1010 viable cells/g, were acquired in Brazil and used for decontamination experiments. Viable and heat-treated microbial biomasses (1.0 mL or g) were mixed with 1 mL of buffered solutions at pH 7.0 and pH 3.0 containing 2.5 μg/mL of FB1 and FB2, incubated 37 °C for 2 h, and analyzed for FB1 and FB2 by chromatographic techniques. Maximum FB1 reduction rates were 27% (LRB), 19.3% (SC1), 8.9% (LR100), 7% (SC2) and 5.7% (LR40). For FB2, the maximum percentages of FBs reduction were 78.8% (SC2), 62.2% (SC1), 55.9% (LR40), 52.2% (LR100) and 38.4% (LRB). Compared with FB1, both viable and heat-treated microorganisms had higher reduction percentages for FB2, especially at pH 3.0, and most heat-inactivated microorganism strains showed higher adsorption rates for FB2 than FB1. Results of this trial indicate that selected heat-inactivated microorganisms are eligible to be tested in animal trials aiming at reducing the toxic effects of fumonisins. Future studies are needed to optimize the adsorption conditions for FBs, such as different contact times and mycotoxin concentrations.