A cellophane membrane method for screening auxotrophic mutants of photochromogenic mycobacteria

A high-resolution screening procedure for the selection of mutants was developed based on the ability of some strains of Mycobacterium smegmatis to produce pigment in the light. Out of 23 000 colonies investigated, 17 auxotrophic mutants were isolated. Specific growth factor requirements for the mutants and the proportion of revertants were determined.