Phenol biodegradation by Candida tropicalis ATCC 750 immobilized on cashew apple bagasse

Abstract

Abstract Phenol biodegradation by cells of Candida tropicalis ATCC 750, both free and immobilized onto cashew apple bagasse, an alternative support widely acknowledged as cheap and abundant, was studied. Microscopy analyses revealed that the yeast was successfully immobilized by adsorption with an efficiency of 45.4%. The best conditions for phenol biotransformation were found to be at 30\u2009°C, pH 6.0, 150 RPM and with 1100\u2009mg\u2009L−1 of initial phenol concentration, for both free and immobilized cells. The adapted and immobilized strain was more resistant to higher phenol concentrations. The metabolic pathway of the phenol biotransformation was the ortho-cleavage of the aromatic ring by the enzyme 1,2-dioxygenase. The biocatalyst showed a high operational stability and the storage studies revealed that 85% of the immobilized cells-CAB remained effectively retained during storage at 4\u2009°C up to 30 days. The results obtained confirm the applicability of cashew apple bagasse as a support matrix for the immobilization of C. tropicalis ATCC 750 and endorses the protocol proposed as a potential biotechnological process for phenolic degradation in industrial wastewater.