title: Optimisation of hydrocortisone production by Curvularia lunata.
abstract: A new method for breeding the hydrocortisone overproducing strain Curvularia lunata by screening ketoconazole-resistance mutant was developed. A hydrocortisone overproducing mutant C. lunata KA-91 with ketoconazole-resistance marker was obtained from protoplasts treated with ultraviolet radiation. The hydrocortisone conversion rate of C. lunata KA-91 was increased by 42.1% compared to the original strain CL-114 at the substrate 17alpha-hydroxypregn-4-en-3, 20-dione-21-acetate addition concentration of 1.0 g/L. The by-products produced by KA-91 were fewer than those of the original strain. It was assumed that the higher cytochrome P450 content of ketoconazole-resistance mutant resulted in the increase of 11beta-hydroxylation capacity. The culture conditions for biotransformation of 17alpha-hydroxypregn-4-en-3, 20-dione-21-acetate to hydrocortisone were optimized by response surface methodology. Plackett-Burman design was applied to elucidate the key factors affecting the hydrocortisone production, and the results indicated that glucose, initial pH, and glucose to total nitrogen sources ratio (omega) had significant effects on hydrocortisone production. Box-Behnken design was employed to search for the optimal parameters of those three key factors. According to the model, the trial checking at the optimal conditions showed a high hydrocortisone conversion rate of 82.67%.
authors.affiliation: School of Bioengineering, Tianjin University of Science and Technology, Tianjin, P.R. China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Lu
authors.forename: Lianxiang
authors.initials: L
authors.lastname: Du
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Jia
authors.forename: Jianping
authors.initials: J
authors.lastname: Wen
authors.forename: Yuping
authors.initials: Y
authors.lastname: Huang
authors.forename: Yawen
authors.initials: Y
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Gong
authors.forename: Huike
authors.initials: H
authors.lastname: Bao
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004351:Drug Resistance; D006854:Hydrocortisone / Q000096:biosynthesis*; D007654:Ketoconazole / Q000494:pharmacology; D015233:Models, Statistical; D008962:Models, Theoretical; D009154:Mutation; D013252:Steroid 11-beta-Hydroxylase / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D003577:Cytochrome P-450 Enzyme System; D013252:Steroid 11-beta-Hydroxylase; D007654:Ketoconazole; D006854:Hydrocortisone