Exogenous calcium ions enhance patulin adsorption capability of Saccharomyces cerevisiae

Patulin contamination is a severe issue that restricts the development of the global fruit processing industry. Yeast adsorbs patulin more effectively than other microbial adsorbents, and this adsorption process mainly depends on the function of the cell wall. Additionally, exogenous calcium ions aid in yeast cell wall formation according to reports. Therefore, in the present study, the effect of exogenous calcium concentrations on the cell wall structure and the patulin adsorption capability was studied. We showed that the ability of the yeast to adsorb patulin was strengthened with an increase in exogenous calcium concentrations between 1×10-4 - 1×10-2 mol/L. Moreover, yeast cell wall thickness, β-1,3-glucan content and the activities of the key catalytic enzymes β-1,3-glucanase and β-1,3-glycosyl transferase were all increased within this range. The results indicated that exogenous calcium activates key enzymes and that these enzymes are crucial for cell wall network formation and patulin adsorption capability.ImportanceThe present work illuminates that the exogenous calcium ions could determine the insoluble network structure by regulating key enzyme activities under certain concentrations, thus indirectly influencing the yeast cell patulin adsorption capability. It could enhance patulin adsorption capability of yeast walls and successfully apply to fruit juice industry.