Bacterial protoplasts from Bacillus species by the action of autolytic enzymes

WHEN certain bacteria are suspended in sucrose solution of suitable concentration and incubated with lysozyme, the rigid cell-walls are dissolved away, leaving relatively stable spherical protoplasts1. Lytic enzymes which dissolve the isolated cell-walls of vegetative Bacillus cereus have been found in extracts of mechanically disintegrated resting spores2 and partial autolysates of sporulating cells3 of this organism. When heat-treated, intact vegetative cells were treated with preparations of these enzymes, the walls were dissolved, leaving the coagulated cell-contents apparently unchanged. It has now been found that when viable organisms are suspended in sucrose solution and treated with these enzymes, relatively stable protoplasts are obtained in good yield.