RESUMO
This paper describes an examination of the cell envelope stability opposite to disruption by chemical and physical methods of extremely halophilic bacteria. The following methods of cell treatment were studied: solvent and chelating agents; pressure shearing at several pressures; ultrasonic disintegration for various times; ballistic disintegration; grinding with cold alumina; lysozyme digestion; osmotic shock; and freezing and thawing. The procedure is based on the determination of three cytoplasmic enzymes released by the cell treatment. Menadione reductase was also used as convenient marker enzyme for damage to the permeability barrier. Of all the methods, only pressure shearing and ultrasonic disintegration yielded a crude extract with high halophilic enzyme activities. These procedures are suitable in designing a cell fractionation scheme for halophilic enzyme purifications.
