title: Enhancement of oxytetracycline production after gamma irradiation-induced mutagenesis of Streptomyces rimosus CN08 strain.
abstract: Streptomyces rimosus CN08 isolated from Tunisian soil produced 8.6 mg l(-1) of oxytetracycline (OTC) under submerged fermentation (SmF). Attempts were made for enhancing OTC production after irradiation-induced mutagenesis of Streptomyces rimosus CN08 with Co(60)-γ rays. 125 OTC-producing colonies were obtained after screening on kanamycin containing medium. One mutant called Streptomyces rimosus γ-45 whose OTC production increased 19-fold (165 mg l(-1)) versus wild-type strain was selected. γ-45 mutant was used for OTC production under solid-state fermentation (SSF). Wheat bran (WB) was used as solid substrate and process parameters influencing OTC production were optimized. Solid-state fermentation increased the yield of antibiotic production (257 mg g(-1)) when compared with submerged fermentation. Ammonium sulphate as additional nitrogen source enhanced OTC level to 298 mg g(-1). Interestingly, OTC production by γ-45 mutant was insensitive to phosphate which opens the way to high OTC production even in medium containing phosphate necessary for optimal mycelia growth.
authors.affiliation: Unité de Microbiologie et Biologie Moléculaire, Centre National des Sciences et Technologies Nucléaires, Technopole de Sidi Thabet, 2020, Tunis, Tunisia.
authors.forename: Hadeer
authors.initials: H
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authors.lastname: Slama
authors.forename: Houda
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authors.lastname: Mankai
authors.forename: Insaf
authors.initials: I
authors.lastname: Barkallah
authors.forename: Ferid
authors.initials: F
authors.lastname: Limam
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