In vivo stability of the complex ochratoxin A - Saccharomyces cerevisiae starter strains

In recent years, several studies have focused on the role of yeasts as adsorbing tools to remove ochratoxin A (OTA) in musts and wines; however, no data are available on the stability of OTA-yeast complex. The present study was designed to assess the ability of five genetically distinct Saccharomyces cerevisiae strains (W13, W28, W46, W47, and Y28), previously studied for their oenological traits and in vitro OTA removal ability, to stably bind the toxin in Uva di Troia grape must (a red variety from Southern Italy). In addition, the effect of temperature, sugar concentration, and addition of ammonium salts on OTA binding was investigated. The highest binding was observed for S. cerevisiae W46 and W28 (42.79e76.44 and 34.51e70.17%, respectively); the other strains (W13, W47 and Y28) removed OTA by 20.34e53.79%. The binding was reversible and the extent of process was strongly affected by the kind of strain. Although the strains W46 and W28 removed OTA efficiently, they did not irreversibly bind OTA (ca. 80e85% release). On the other hand, the complex “S. cerevisiae W13-OTA” exhibited the greatest stability (ca. 55% release). The results obtained may be relevant not only to improve wine safety by integrating the binding ability in the criteria of selection of wine starters, but also for a more general biotechnological purpose, because of the increasing interest in the bioremediation of musts and wines using yeasts.