Printed in Great Britain The Occurrence and Genetics of Some COP Mutants in Streptomyces coelicolor

We have isolated auxotrophic mutants of Streptomyces coelicolor which can grow on a minimal medium without growth factors when the gas phase is supplemented with C02. Usually they have an alternative requirement for a specific growth factor such as arginine, purines or vitamins. Some of the C02 mutants resemble those already known in Neurospora crassa and Escherichia coli but others present novel phenotypes