[The use of the protoplast method for the selection of oleandomycin producers].

The use of protoplasting with subsequent reversion to the cellular form in improvement of the oleandomycin-producing organism provided a 110% increase in the range of culture variation with respect to the antibiotic production property. A regenerant with a potency of 12 to 20 per cent higher than that of the initial strain which produced 30 per cent lower amounts of dark pigments of melanin nature was isolated. Repeated protoplasting and regeneration of the regenerant provided a very low regeneration frequency i.e. 0.0002%. The potency of all the secondary regenerants was low.