A simple method for cell disruption by immobilization of lysozyme on the extrudate-shaped NaY zeolite

Lysozyme was immobilized on the extrudate-shaped NaY zeolite and was used for the disruption of Micrococcus lysodeikticus cells in a well-agitated contactor. The influences of specific operating parameters on the density and activity of immobilized lysozyme were investigated. The result for the maximum activity of immobilized lysozyme was observed at pH 8 and the immobilized specific activity decreased significantly with increasing ionic strength of buffer. Simultaneously, the specific activity of immobilized lysozyme decreased with the amount of enzyme added. Based on these results, the influences of operating parameters on the efficiency of cell disruption by using lysozyme-zeolite complex were further examined. The efficiency of cell disruption was evaluated in terms of the amount of released protein and the percentage of disrupted cells, and compared with other supports and mechanical disruption methods. The results showed that the amount of released proteins and the percentage of disrupted cells in the lysates by using lysozyme-zeolite complex were much higher than those values reported in the literature by using other supports and mechanical disruption systems. After 12 successive cycles, the released protein from disrupted cells decreased and approached to the stationary value of 33.3%, as compared with the first cycle. In order to determine the reusability of lysozyme-zeolite complex, the adsorption–desorption cycle was investigated. The results showed that the density of immobilized lysozyme did not change significantly during the repeated adsorption–desorption operations.