title: Change in colony morphology and kinetics of tylosin production after UV and gamma irradiation mutagenesis of Streptomyces fradiae NRRL-2702.
abstract: Tylosin is a macrolide antibiotic used as veterinary drug and growth promoter. Attempts were made for hyper production of tylosin by a strain of Streptomyces fradiae NRRL-2702 through irradiation mutagenesis. Ultraviolet (UV) irradiation of wild-type strain caused development of six morphologically altered colony types on agar plates. After screening using Bacillus subtilis bioassay only morphological mutants indicated the production of tylosin. An increase of 2.7+/-0.22-fold in tylosin production (1500mg/l) in case of mutant UV-2 in complex medium was achieved as compared to wild-type strain (550mg/l). Gamma irradiation of mutant UV-2 using (60)Co gave one morphologically altered colony type gamma-1, which gave 2500mg/l tylosin yield in complex medium. Chemically defined media promoted tylosin production upto 3800mg/l. Maximum value of q(p) (3.34mg/gh) was observed by mutant gamma-1 as compared to wild strain (0.81mg/gh). Moreover, UV irradiation associated changes were unstable with loss of tylosin activity whereas mutant gamma-1 displayed high stability on subsequent culturing.
authors.affiliation: Bioprocess Technology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, Pakistan.
authors.forename: Shazia
authors.initials: S
authors.lastname: Khaliq
authors.forename: Kalsoom
authors.initials: K
authors.lastname: Akhtar
authors.forename: Muhammad
authors.initials: M
authors.lastname: Afzal Ghauri
authors.forename: Ruqia
authors.initials: R
authors.lastname: Iqbal
authors.forename: Ahmad
authors.initials: A
authors.lastname: Mukhtar Khalid
authors.forename: Muhammad
authors.initials: M
authors.lastname: Muddassar
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000528:radiation effects; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism; D005285:Fermentation / Q000528:radiation effects; D005720:Gamma Rays; D007700:Kinetics; D016296:Mutagenesis; D009584:Nitrogen / Q000378:metabolism; D013302:Streptomyces / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D015645:Tylosin / Q000096:biosynthesis* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D002244:Carbon; D009584:Nitrogen; D015645:Tylosin