Oxytetracycline production in solid state and submerged fermentation by protoplast fusants of Streptomyces rimosus

Abstract

Streptomyces rimosus TM-55 was treated with 3% EMS, and 29 auxotrophic mutants (AM-1 - AM-29) were isolated from 5457 colonies at a survival rate between 6.6-66.7%. Three sets of the auxotrophic mutants, AM-3 and AM-27, AM-7 and AM-28, and AM-3 and AM-21, were chosen for protoplast fusion with 50% PEG 1000 for 30 minutes at 25 degrees C, and 25 fusants were isolated (f-1 - f-25). In solid substrate, oxytetracycline production of 20% fusants was higher than that of the wild strain, while in submerged fermentation, it was 44%. Oxytetracycline productions of fusants f-1, f-6, f-11, f-12, f-20 and f-21 were lower than that of the wild strain in solid substrate, but this was reversed in submerged fermentation. On the other hand, OTC production of fusant f-8 was higher than that of the wild strain in solid substrate, and this was reversed in submerged fermentation.