Immobilization of permeabilized cells of baker’s yeast for decomposition of H₂O₂ by catalase

Permeabilization is one of the effective tools, used to increase the accessibility of intracellular enzymes. Immobilization is one of the best approaches to reuse the enzyme. Present investigation use both techniques to obtain a biocatalyst with high catalase activity. At the beginning the isopropyl alcohol was used to permeabilize cells of baker’s yeast in order to maximize the catalase activity within the treated cells. Afterwards the permeabilized cells were immobilized in calcium alginate beads and this biocatalyst was used for the degradation of hydrogen peroxide to oxygen and water. The optimal sodium alginate concentration and cell mass concentration for immobilization process were determined. The temperature and pH for maximum decomposition of hydrogen peroxide were assigned and are 20°C and 7 respectively. Prepared biocatalyst allowed 3.35-times faster decomposition as compared to alginate beads with non permeabilized cells. The immobilized biocatalyst lost ca. 30% activity after ten cycles of repeated use in batch operations. Each cycles duration was 10 minutes. Permeabilization and subsequent immobilization of the yeast cells allowed them to be transformed into biocatalysts with an enhanced catalase activity, which can be successfully used to decompose hydrogen peroxide.