STUDIES ON THE CELL WALL LYTIC ENZYMES PRODUCED BY STREPTOMYCES SPECIES

PART 1. THE STRAINS AND THEIR LYTIC ACTIVITY TOWARD SACCHAROMYCES

Abstract

In order to obtain microorganisms which produce lytic enzyme active against cell walls of Saccharomyces cerevisiae, samples collected from soil were spread on an agar medium containing heat-treated baker's yeast. In the initial screening, about 150 colonies which showed clear zones on the medium around them were selected. In the second test the lytic activity of the culture liquid of these isolates were measured by means of the cup-assay method. Among them eight strains of Streptomyces were found to be active and nine strains of bacteria active to a lesser extent.
By means of the turbidimetric assay, the culture liquids of all eight strains of Streptomyces also exhibited lytic activity toward heat-treated cells of Saccharomyces cerevisiae in two hours incubation. Among the eight strains of Streptomyces, strain no. 62 was selected and studied further, because it showed the strongest lytic activity and produced the lytic factor for an extended time. The lytic factor produced by the strain was concentrated by ammonium sulfate precipitation. Living cells of Saccharomyces cerevisiae proved to be lysed by the concentrated lytic factor in short period.