Celluloseless Mutants of certain Acetobacter Species

Summary: The occurrence has been studied of mutants which did not produce extracellular cellulose in cultures of two strains of Acetobacter acetigenum (NCIB8132, NCIB5346) and one strain of A. xylinum var. africanum (NCIB7029). With about 150 glucose yeast-extract (GYE) medium static cultures of organism NCIB8132, prepared over a period of about one year, cellulose pellicles were produced in each case. In contrast, the loss of cellulose-forming ability and the appearance of diffuse general growth were noted with 6 out of 26 tests made with static cultures in an ethanol yeast-extract (EYE) medium, 3 out of 905 isolates selected from platings of GYE shaken cultures, and 1 out of 3 tests made with EYE shaken cultures. By a ‘mass-plating’ technique it was found that mutants which did not produce cellulose pellicles (‘celluloseless mutants’) were present in cellulose-producing cultures. The two other cultures (NCIB5346, NCIB7029) underwent mutation spontaneously in GYE static cultures on several occasions.