Probiotic Gut-Borne Saccharomyces cerevisiae Strain With Fumonisin B1 Decontamination Properties. Statistical Optimization For Biomass Production

ROMINA ARMANDO; ; CECILIA DOGI, ; MIGUEL GALVAGNO, ; *SOFIA SCHULZE, ; ANA DALCERO,; LILIA CAVAGLIERI

Congreso; MYCORED North America 2012; 2012

The present study was developed to examine the ability of Saccharomyces cerevisiae RC016 strain (isolated from animal niche with probiotic properties), to bind fumonisin B1 (FB1) in vitro. In addition, systematic and statistical optimization for yeast fermentation was carried out, to obtain a probiotic feed additive intended to perform animal health and also to be economically profitable. The FB1 binding assay was performed using a stock solution of FB1 suspended in Phosphate Buffer Solution (PBS) to obtain the concentrations 1; 5; 20 and 50 µg ml-1. Yeasts (107cells ml-1) were washed twice with PBS and incubated for 1 h at 37ºC in a shaking bath with 1 ml FB1. Then, cells were pelleted by centrifugation at 5,000 rpm at room temperature for 15 min, and the supernatant containing unbound mycotoxin was collected for high-performance liquid chromatography (HPLC) analysis. Each adsorption test was performed in triplicate and controls were performed. Statistical optimization for biomass production of S. cerevisiae RC016 was performed by designing Plackett-Burman and methodology of Central Composite Design (CCD). The validation of the statistical model was carried out through fermentation in bioreactors. The percentages of FB1 bound by Saccharomyces cerevisiae RC0016 ranged from 17% to 77.3%. The amount of FB1 binding varied according to the used mycotoxin concentration. The yeast was able to increase the toxin removal as the mycotoxin concentration increased. Statistical optimization of S. cerevisiae RC016 biomass production was performed in media with molasses at 28°C and 250 rpm. At the first optimization stage using the Plackett-Burman designing, the molasses, yeast extract concentrations, and incubation period were further optimized by the central composite design (CCD) methodology in order to understand their interaction and to determine their optimal levels. The results indicated that the optimum biomass production was reached in a medium containing 17% molasses and 4.6 g l-1 yeast extract, after 60 h incubation period. At these conditions, the model predicts a maximum response for the S. cerevisiae RC016 biomass production. Saccharomyces cerevisiae RC016 was able to reduce FB1 in appreciable quantities. A general improvement in biomass production was achieved as a result of the optimization process. These results indicate the importance of statistical tools in the design of the culture conditions to increase the production of yeasts able to reduce mycotoxin levels and also to minimize production costs.