Improvement in cell-bound phytase activity ofPichia anomalaby permeabilization and applicability of permeabilized cells in soymilk dephytinization

Abstract

Whole cell permeabilization of Pichia anomala to ameliorate the cell-bound phytase activity and usability of permeabilized cells in dephytinization of soymilk. The cells of P. anomala were subjected to permeabilization using the surfactant Triton X-100 to overcome the permeability barrier and prepare whole cell biocatalysts with high phytase activity. The statistical approach, response surface methodology (RSM) was used to optimize the operating conditions for permeabilization. The treatment of cells with 5% Triton X-100 for 30 min resulted in c. 15% enhancement in cell-bound phytase activity. The shrinkage of protoplast was observed, although cell viability and phytase stability were not significantly altered. The free as well as immobilized permeabilized cells hydrolysed soymilk phytate, and the latter could be reused over four consecutive cycles. Whole cell permeabilization of P. anomala using Triton X-100 led to enhancement in cell-bound phytase activity. The viability and integrity of yeast cells were not significantly affected because of permeabilization. The permeabilized P. anomala cells effectively dephytinized soymilk, and the permeabilized cells immobilized in alginate could be reused because of sustained phytase activity. This is the first report on the use of permeabilized yeast cells for mitigating phytate content of soymilk. Alginate entrapment of permeabilized P. anomala allows reuse of cells for soymilk dephytinization, thus suggesting a potential application in food industry.