In vitro evaluation of the ability of Lacticaseibacillus rhamnosus and Saccharomyces cerevisiae strains to bind...

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.