Spontaneous mutation of polysaccharide production in Alcaligenes faecalis var. myxogenes 10C3

Alcaligenes faecalis var. myxogenes 10C3, which produces large amounts of succinoglucan and small amounts of curdlan, was genetically unstable and mutated spontaneously to a form producing more curdland than succinoglucan when stocked on nutrient agar slants. The mutation occurred in the absence of cell division when the cells were incubated in saline and was enhanced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine, ethyl methane sulfonate, or ultraviolet light. Mutant strains were genetically stable and did not revert spontaneously for at least 1 year when stocked on nutrient agar slants.