Control of ammonium ion level for efficient nanaomycin production.

Abstract
The addition of a small amount of NH4+ to a complex medium increased nanaomycin production by Streptomyces rosa ssp. notoensis OS-3966. The best NH4+ donor for nanaomycin production was NH4+-saturated natural zeolite, with which the maximum titer of nanaomycin E was 760 .mu.g/ml, about 4-fold higher than the control titer. Lowering NH4+ levels by adding NH4+-trapping agents such as untreated natural zeolite reduced antibiotic [antibacterial and antifungal drug] production.