Induction of the Enzymes that Degrade Chitin and Chitosan from Enterobacter sp. G-1

Enterobacter sp. G-1 produced both chitinolytic and chitosanolytic enzymes when the carbon source was slightly deacetylated chitin or its oligomer, but not when the carbon source in a medium was highly deacetylated chitosan or its oligomer. Synthesis of these enzymes was not inhibited by chitosan, but was promoted in proportion to the amount of added chitin. The synthesis was induced by insoluble chitin or by its oligomers, but not by its monomer. These results indicate that Enterobacter sp. G-1 produces both chitinolytic and chitosanolytic enzymes in response to an N acetyl group in chitin, and that when there are more N-acetyl groups the production of the enzyme is higher, which led to more cell divisions. The results of cultures in which GlcNAc2 is the only carbon source led us to conclude that GlcNAc2 does not directly enter the cell. Instead, GlcNAc derived from GlcNAc2 is metabolized. However, GlcNAc did not induce production of both enzymes. These results imply that Enterobacter sp. G-1 secretes the enzymes after recognizing insoluble chitin or its oligomers. Then the monomer enters the cell and is metabolized by the bacteria.
Key words: Enterobacter sp. G 1; chitinolytic and chitosanolytic enzymes; chitin; chitosan.