Adsorption of Aflatoxin by bio-adsorbents

MAGNOLI A.P.; MONGE M.P.; ROJO M.C.; COMBINA M.; DALCERO A.M.; CHIACCHERA S.

Carlos Paz

Conferencia; 13th Latin American Conference on Physical Organic Chemistry (CLAFQO-13); 2015

Universidad Nacional de Cordoba

Mycotoxins which are numerous and widely distributed in the nature are the origin of serious problems in food industry. Survey of microflora and mycotoxins detection in avian feeds, conducted in our research group demonstrated the presence of the major toxigenic genus (Aspergillus, Penicillium y Fusarium) and their associated mycotoxins. Aflatoxin B1 (AFB1) is the most important mycotoxin from the point of view of its impact on poultry feed, toxicity and impact on the economy. One of the most practical approaches to the mycotoxin problems in poultry feed is the use of non nutritive adsorbent agents incorporated into the diets of birds. These substances, sequester the toxins in the gastrointestinal tract forming insoluble complexes that are eliminated with the feces. The adsorbents can also sequester other important molecules from the birds diets, such as amino acids and/or vitamins among others, causing nutrition or health problems to the birds. Some additives from biological origin, such as yeasts or wall cell yeast, have demonstrated effectiveness in preventing acute aflatoxicosis. Yeast are capable of sequestering aflatoxin (AFs) through interaction with cell wall components. The aim of this study was to determine whether yeasts isolated from feces and feeds of broilers have in vitro capacity to adsorb AFs. The methodology proposed by Gusils et al. (2002) and Fraga et al. (2007) was used. The yeasts isolated were morphologically characterized according to Pitt and Hocking (1999), with subsequent confirmation by sequencing the domain D1/D2 of the gene ribosomal 26S. The sequences data were compared with a database using BLAST. Aflatoxins were produced via fermentation of rice by A. parasiticus NRRL 2999. The toxin was extracted with chloroform and was kept dry until flash chromatography purification. The pure toxin was quantified by UV-visible spectroscopy and further confirmed by HPLC. Different Bioadsorbentes were evaluated on their ability to adsorb AFs. The adsorption is estimated by comparing the quantity of AFs in the supernatant before and after incubation. Quantitation was performed by HPLC. The pure toxin was quantified by UV-visible spectroscopy and further confirmed by HPLC. Different bioadsorbentes were evaluated on their ability to adsorb AFs. The adsorption was estimated following the depletion of the toxin in the supernatant after the adsorption. The complex AFs-bioadsorbent was obtained by the addition of succesive AFs aliquots to a given mass of adsorbent, which was carefully separated from the supernatant by centrifugation between each addition. The mass AFs/g of bioadsorbent was estimated and the complex was analized by FTIR. The identification by sequencing the domain D1/D2 of the ribosomal gene 26S resulting in the following cepas Clavispora lusitaniae, Cyberlindnera fabianii of feces and Pichia kudriavzevii, Clavispora lusitaniae of balanced food. The genes sequence showed 100% identities. All strains used in the present study were able to in vitro adsorb AFs. The adsorption Isotherms showed either Langmuir or slightly sigmoid behaviors, and showed differences in the AFs maximum adsorption capacity among the assayed yeasts. The spectroscopy IR was not sensitive enough to detect the toxin on bioadsorbent surface.