L-Asparaginase Release from Escherichia coli Cells with K2HP04 and Triton XIOO

A method to release L-asparaginase (EC 3.5.1.1) from ATCC Escherichia coli 11303 cells by chemical permeabilization was studied. It was found that a combination of K2HP04 and Triton XIOO was effective. The influences of K2HP04 concentration, Triton concentration, E. coli cell concentration and pH on the release of enzyme and proteins were investigated in detail. Experimental results showed that 12.5% (w/v) K2HP04, 2% (w/v) Triton XIOO and 3 x 10^ cells/mL made the amount of enzyme released over 70%. L-Asparaginase in K2HP04 and Triton solution could remain stable at least for 24 h. The release effect of K2HP04 and Triton XIOO used simultaneously was better than that of K2HP04 and Triton XIOO used separately in succession. Electron microscopy indicated that the chemical treatment altered the surface structure of E, coli cells but did not break them. As the method does not produce a large amount of cell fragments and the amount of enzyme released is relatively high, it can be thought to be an valuable and economic method to release intracellular enzyme.