Hydrolysis of Walls and Formation of Sphaeroplasts in Mucor rouxii

Abstract

SUMMARY Walls from Mucor rouxii were partially lysed by an enzymatic complex present in filtrates from cultures of Streptomyces sp. When germinated spores were incubated with the enzymatic complex in a protective medium, osmotically sensitive sphaeroplasts were formed. The enzyme responsible for the degradation of the wall showed optimum activity at pH 7·5 and 32 °C. It was susceptible to the presence of divalent cations. The enzymatic complex released hexosamines (but no N-acetyl hexosamines), neutral sugars and uronic acids from purified walls of the fungus. A wall-bound α-glucosidase was also rendered soluble by the enzyme. The enzymatic complex hydrolysed chitosan, but not chitin or mucoran, and hydrolysed the walls from only fungi belonging to the Mucorales. It is suggested that the hydrolytic capacity of filtrates from cultures of Streptomyces sp. developed in the presence of walls from M. rouxii was due to an enzyme (chitosanase), acting on chitosan but not on chitin.