Adsorption of aflatoxin B1, Fumonisin B1 and zearalenona by Saccaromyces cerevisiae strains isolated from animal ecosystem

ARMANDO, ROMINA; PIZZOLITO ROMINA; SALVANO, MARIO; DOGI, CECILIA ANA; GERBALDO, GISELA; GONZALEZ PEREYRA, MARÍA; DA ROCHA ROSA, CARLOS; DALCERO, ANA; CAVAGLIERI, LILIA

Viena, Austria

Congreso; ISM Conference: Worldwide Mycotoxin Reduction in Food and Feed Chains; 2009

International Society for Mycotoxicology

POSTER 077 The purpose of the present study was to evaluate the aflatoxin B1 (AFB1) adsorption capacity of yeast cells harvested from S. cerevisiae strains obtained from animal ecosystem. In previous studies we showed the gastrointestinal tract tolerance of these yeasts. Cells were grown on Yeast Peptone Dextrose medium for 24 h at 37 ¨¬C. A solution of AFB1 at 0.25; 0.5; 1; 5; 20 and 50 ¥ìg/ml in PBS was prepared. Yeasts (1 x 107 cell/ml) were incubated for 30 min at 37¨¬C with 1 ml phosphate-buffered saline (PBS) containing AFB1 at different AFB1 was collected. The same methodology was applied with fumonisin B1 (FB1) and zearalenone (ZEA). All tested mycotoxins were quantified by HPLC with fluorescence detector. The results were evaluated by determining the number of binding sites of mycotoxin (M), the equilibrium constant involved in the process (Keq) and the adsorption efficiency (E = M x Keq). According to this adsorption model, all the assayed strains were able to adsorb similar amounts of AFB1. The AFB1 adsorption levels varied from 9 x 10-9 ¥ìg AFB1/cell to 3 x 10-9 ¥ìg AFB1/cell with an adsorption efficiency that ranged from 4 x 1012 to 9 x 1013 . The ZEA adsorption levels and the process efficiency was similar than AFB1. Although all strains showed a high efficiency in FB1 adsorption, only S. cerevisiae RC008 was the most effective (E = 3.8 x 1015). In general, S. cerevisiae RC008 and S. cerevisiae RC017 had the highest Keq (from 1.7 x 104 to 1 x 108), showing the low reversibility of the adsorption process of the tested mycotoxins. Adsorption isotherm in biological systems is a reversible process that can be characterized as a chemical equilibrium. As a result, adsorption is a concentration-dependent process influenced by mycotoxin concentration, the amount of adsorbent, and the relative affinity of the adsorbent for the mycotoxin. The assay that we conducted demonstrates the potential useful of S. cerevisiae RC008 and RC017 to overcome problems associated with mycotoxins contaminated feeds.