Scientific Reports of the Faculty of Agriculture, Okayama University
Published by the Faculty of Agriculture, Okayama University
ONLINE ISSN : 2186-7755

Improvement of Sinefungin-Producing Strain of Streptomyces incarnatus by Conferring Rifampicin-Resistance through Ultraviolet Light Irradiation and Protoplast Regeneration

Li, Yin Shu
Tanaka, Hidehiko
Inagaki, Kenji Kaken ID researchmap
Abstract
Secondary metabolite production by gram-positive bacteria is strictly regulated at the transcription of the biosynthetic genes to mRNA in response to certain stringent conditions. Therefore, some mutational disruption of regulatory domains of the bacterial RNA polymerase might increase the production of the antibiotics. In this study, we have attempted to improve the sinefungin-producing strain of Streptomyces incarnatus NRRL 8057 by irradiating ultraviolet light on the protoplast, and selecting mutants that acquired the resistance to rifampicin, the antibiotic which specifically binds to the β-subunit of bacterial RNA polymerase. After three rounds of mutation, 10 strains were obtained with varied resistance to rifampicin. A mutant which showed the highest resistance was found to have the highest sinefungin production, which was 2.4 times higher(0.45±0.11μg/ml)than the wild type strain (0.19±0.07μg/ml). The breeding approach by rifampicin-resistance may be advantageous over the classical random screening since it requires much smaller number of candidates to be examined.
Keywords
Sinefungin
Protoplast regeneration
Rifampicin
RNA polymerase
ISSN
0474-0254
NCID
AN00033029