Improvement of the productivity of elasnin, a specific elastase inhibitor, by Streptomyces noboritoensis KM-2753.

Streptomyces noboritoensis KM-2753, an elasnin-producing strain, co-produces an antimycin complex and its elasnin productivity is low (0.006 mg/ml). To obtain mutants possessing higher degrees of elasnin productivity and deficient in antimycin production, the strain was treated with N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ultraviolet light, acriflavine (AF) and high temperature. Mutant N-134 obtained by treatment with NTG was 108 times higher than the original strain in elasnin productivity and produced no antimycin. Strain AF-17 obtained by AF treatment and strain H-80 obtained by incubation at high temperature showed 715 and 428 times higher productivities than that of the original strain, respectively. The productivity of elasnin was further increased 1.6 approximately 2.6 times by addition of saturated fatty acids, especially lauric acid, to the culture. Consequently, strain AF-17 produced 11.1 mg/ml of elasnin in the presence of 10 microgram/ml of lauric acid.