Chemical moieties and interactions involved in the binding of zearalenone to the surface of Lactobacillus rhamnosus strains GG

Abstract

Viable, heat-and acid-killed Lactobacillus rhamnosus strain GG (LGG) has shown high binding properties with zearalenone (ZEN). To identify the type of chemical moieties and interactions involved in binding with the ZEN, LGG was subjected to different chemical and enzymatical treatments, prior to the binding experiments. Pretreating the viable, heat- and acid-killed bacteria with m-periodate significantly decreased ZEN binding, suggesting that ZEN binds predominantly to carbohydrate components. Pretreatment with Pronase E had no effect on the ability of viable cells to bind ZEN, however, a reduction in the binding of ZEN by heat- and acid-killed cells, suggesting that the new binding sites exposed by heat or acid are proteins in nature. Pretreatment with urea also decreased binding, suggesting that hydrophobic interactions play a role in ZEN binding. The binding of ZEN in concentrations ranging from 0.79 to 62.82 μM and its subsequent dissociation by repetitive aqueous washes was also studied. The binding sites of the bacteria were not saturated by the maximum ZEN concentration studied.