Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

Hydrogen peroxide (HP) is a promising chemical sanitizer for use in the food industry. Its residues have to be decomposed, usually using an enzyme process employing catalase. In order to offer an inexpensive biocatalyst and to simplify subsequent manipulation, we have prepared magnetically responsive alginate beads containing entrapped Saccharomyces cerevisiae cells and magnetite microparticles. Larger beads (2-3 mm in diameter) were prepared by dropping the mixture into calcium chloride solution, while microbeads (the diameter of majority of particles ranged between 50 and 100 microm) were prepared using the water in oil emulsification process. In general, microbeads enabled more efficient HP decomposition. The prepared microparticulate biocatalyst caused efficient decomposition of HP in water solutions (up to 2% concentration), leaving very low residual HP concentration after treatment (below 0.001% under appropriate conditions). The biocatalyst was stable; the same catalytic activity was observed after one month storage at 4 degrees C, and the microbeads could be used at least five times.