The substance, which acted on the mycelial cells of
Asp, oryzae was found in the culture fluid of a newly isolated bacterial strain. This organism seemed to belong to
Bacillus circulans: gram-negative, spore-forming rods, (spore: oval, terminal to subterminal), motile, peritrichous flagella, reduces nitrate, acetylmethyl-carbionl-negative, acid from glucose-without gas. This active material was an enzyme with an optimum pH at 6.8, and precipitated in a 40-60% saturated solution of ammonium sulfate. The enzyme acted on the cell-wall and liberated hexose-polymer from the cell-walls of
Asp. oryzae. but could not liberate any hexosamine or amino acid. This liberated hexose- polymer seemed to be a polymer of melibiose consisting of glucose and galactose. It seems that the polysaccharide is a cementing and coating material of the network of chitin fiber of the cell-walls. Specificity of the enzyme was very broad; the enzyme acted on the living cells of
Asp, sojae, Mucor Mu-5,
Pen. purpurogenum var., and heat treated cells of
Saccharomyces saké, but was inactive on
Rhizopus javanicus.
This result may be assumed to indicate that the structure of the cell- wall of
Asp. sojae, Pen. sp., and
Mucor are similar to
Asp. oryzae, but that of
Rhizopus is different.
This enzyme was produced during the sporulation of
Bacillus circulans.
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