Efficiency of Different Sources of Saccharomyces cerevisiae to Bind Aflatoxin B1 in Phosphate Buffer Saline

摘要

Aflatoxins, a group of carcinogenic mycotoxins, can cause acute and chronic intoxications and also liver cancer in humans and animals. Aflatoxin B1 (AFB1) is the most potent, having proven toxic properties. Biological decontamination of mycotoxins is one of the well-known strategies for management of mycotoxins in foods and feeds, presenting some advantages over physical and chemical methods. Among the different possible decontaminating microorganisms, Saccharomyces cerevisiae is a potential group since it is widely used in preservation and food fermentation. Saccharomyces cerevisiae cell wall consists of a network of β-1,3 glucan back bone with β-1,6 glucan side chains, which is attached to highly glycosylated mannoproteins making the external layer. Binding of different mycotoxins to yeast cell surface has been reported. This study was carried out to investigate the efficiency of S. cerevisiae to remove AFB1 in Phosphate Buffered Saline (PBS) solution (pH 7.3 25°C). Saccharomyces cerevisiae concentration from four different sources (dried yeast of sugar cane, autolyzed yeast, cell wall and brewery dehydrated residue) was determined by a Neubauer-counting chamber, using 1x1010 non-viable cells for each 3.0 mL of PBS containing 0.5μg L-1 AFB1. The assay was performed at contact times of 5, 10, 20 and 30 minutes. Among all analyzed yeasts, the dried yeast of sugar cane presented highest removal capacity of AFB1, with an average reduction of 98.3%. Autolyzed yeast and brewery dehydrated residue presented extensive removal capacity, with averages of 93.8 and 84.6%. The yeast cell wall showed the lowest removal capacity (82%).