Factors Influencing Growth and Polysaccharide Formation by Strains of Chromobacterium Violaceum.

Corpe, William A. (Columbia University, New York, N.Y.). Factors influencing growth and polysaccharide formation by strains of Chromobacterium violaceum. J. Bacteriol. 88:1433-1441. 1964.-Gelatinous Chromobacterium violaceum strains elaborate a fibrous exopolysaccharide that forms a matrix in which growing cells are embedded. Stable, nongelatinous variants arising from gelatinous cultures were of two types: (i) those that had lost the ability to produce polysaccharide, and (ii) those that had lost the capacity to bind the polymer into a matrix. Gelatinous strains growing in Tryptone did not produce a matrix, but rather elaborated polysaccharide free into the medium. The effect of Tryptone was not one of selection of nongelatinous variants. Growth and polysaccharide synthesis in a defined medium were greatest when amino acids were substituted for ammonia as a nitrogen source. Best growth and polysaccharide yield occurred when the ratio of carbohydrate to nitrogen was in the order of 10:1. Depolymerization of formed polymer occurred in cultures grown with Casamino Acids as the nitrogen source. Calcium ion stimulated polysaccharide formation. Iron, although stimulating growth, inhibited polysaccharide formation.