Enhancement of wanlongmycin production by nitrogen ion beam implantation
Financial support: National Natural Science Foundation of China (No. 30471161) and the Guangdong Natural Science Foundation of China (No. 8151064001000010 and No.06025388).
Keywords: mutagen nitrogen ion beam implantation, Streptomyces griseovariabilis GAAS2057, wanlongmycin.
In an attempt to obtain an industrial strain with higher yield of wanlongmycin, the wild strain Streptomyces griseovariabilis GAAS2507 was mutated by a novel mutagen, nitrogen ion beam with energy of 20 kilo electron volts (KeV) and dose ranging from 7.80 x 1014 to 2.86 x 1015 ions/cm2. One mutant strain WN939 was obtained. Its yield of wanlongmycin reached 271.24 µg/mL, which was 82.10% higher than that of the wild strain. The mutant strain WN939 was relatively stable for the production of wanlongmycin through six successive transfers of cultures and a repeat fermentation in a 30 L fermentor. In addition, the mutant strains were investigated and divided into five types by their colony phenotypes and production of wanlongmycin. Among them, three types mutant strains exhibited positive mutation, while the other two types mutant strains exhibited negative mutation.