Conservation of the Biocatalytic Activity of Whole Yeast Cells by Supported Sol-Gel Entrapment for Efficient Acyloin Condensation
In this study, an efficient and generally applicable 2nd generation sol-gel entrapment method was developed for immobilization of yeast cells. Cells of Lodderomyces elongisporus, Candida norvegica, Debaryomyces fabryi, Pichia carsonii strains in admixture with hollow silica microspheres support were immobilized in sol-gel matrix obtained from polycondensation of tetraethoxysilane. As biocatalysts in the selective acyloin condensation of benzaldehyde catalyzed by pyruvate decarboxylase of the yeast, the novel immobilized whole-cell preparations were compared to other states of the cells such as freshly harvested wet cell paste, lyophilized cells and sol-gel entrapped preparations without hollow silica microspheres support. Reusability and storability studies designated this novel 2nd generation sol-gel method as a promising alternative for solid formulation of whole-cells bypassing expensive and difficult downstream steps while providing easy-to-handle and stable biocatalysts with long-term preservation of the biocatalytic activity.