Biosorption of patulin from apple juice by caustic treated waste cider yeast biomass

Waste cider yeast is a natural by-product generated through the production of fermentable beverages. In this work, the biosorption of patulin (PAT) from apple juice using waste cider yeast was investigated. The yeast cells were treated with caustic, ethanol and heats. Among the treatments, the highest PAT uptake (58.29%) was obtained with the caustic treated waste yeast. The effects of pH and initial concentration of PAT were assessed. The results showed that the adsorption percentage of PAT increased simultaneously with the increase of pH and approached equilibrium at pH 4.5. The removal of PAT increased with decreasing of toxin levels. The experimental data were analyzed using the Langmuir and Freundlich equations. It has been observed that the adsorption equilibrium was best described by the Langmuir model. The Langmuir constants were qmax (μg/g) = 8.1766 and b (L/mg) = 0.0640. In packed bed column studies, it was found that Ca-alginate gel was a good biosorbent for PAT removal and immobilized caustic treated yeast particles in the gel increased the biosorption capacity of the gel.