Elimination of by-products in 11β-hydroxylation of Substance S using Curvularia lunata clones regenerated from NTG-treated protoplasts

Wilmańska, Danuta; Milczarek, Krystyna; Rumijowska, A.; Bartnicka, Katarzyna; Sedlaczek, L

doi:10.1007/bf00240738

Cited by 30 publications

(15 citation statements)

References 12 publications

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“…The wild saprophitic strain of C. lunata (IM 2901) used in this study is known for its ability of cortexolone 11b-hydroxylation with a high efficiency in hydrocortisone production-a pharmauceutical corticosteroid of significant value (Wilmań ska et al 1992;Paraszkiewicz and Długoń ski 1998). This fungus produces also with high efficiency an extracellular, slime polymer capable of stabilising oil in water emulsions-mixtures in which hydrophobic phase is dispersed as microscopic droplets in water phase (Kanwal et al 2001;Paraszkiewicz et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Enhancement of emulsifier production by Curvularia lunata in cadmium, zinc and lead presence

et al. 2006

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The influence of cadmium, zinc and lead on fungal emulsifier synthesis and on the growth of filamentous fungus Curvularia lunata has been studied. Tolerance to heavy metals established for C. lunata was additionally compared with the sensitivity exhibited by strains of Curvularia tuberculata and Paecilomyces marquandii-fungi which do not secrete compounds of emulsifying activity. Although C. lunata, as the only one out of all studied fungi, exhibited the lowest tolerance to heavy metals when grown on a solid medium (in conditions preventing emulsifier synthesis), it manifested the highest tolerance in liquid culture - in conditions allowing exopolymer production. Cadmium, zinc and lead presented in liquid medium up to a concentration of 15 mM had no negative effect on C. lunata growth and stimulated emulsifier synthesis. In the presence of 15 mM of heavy metals, both the emulsifier and 24-h-old growing mycelium exhibited maximum sorption capacities, which were determined as 18.2 +/- 2.67, 156.1 +/- 10.32 mg g(-1) for Cd2+, 22.2 +/- 3.40, 95.2 +/- 14.21 mg g(-1) for Zn2+ and 51.1 +/- 1.85, 230.0 +/- 28.47 mg g(-1) for Pb2+ respectively. The results obtained by us in this work indicate that the emulsifier acts as a protective compound increasing the ability of C. lunata to survive in heavy metal polluted environment. Enhancement of exopolymer synthesis in the presence of Cd2+, Zn2+ and Pb2+ may also suggest, at least to some extent, a metal-specific nature of emulsifier production in C. lunata. Due to accumulation capability and tolerance to heavy metals, C. lunata mycelium surrounded by the emulsifier could be applied for toxic metal removal.

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Section: Introductionmentioning

confidence: 99%

Enhancement of emulsifier production by Curvularia lunata in cadmium, zinc and lead presence

et al. 2006

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“…The possible reason might be that the wall of conidia was thick and insensitive to mutagenic treatment. Furthermore, the multinucleate conidia and hyphal fragments could result in mixed cultures, which were unsuitable for stable mutant strain selection, as well as in the loss of the potential mutant strains by the "rescue" repair of the DNA from undamaged nuclei [3]. By treatment of the uninucleate fractions of C. lunata protoplasts with UV, the desired mutant strains could be obtained with a relative high frequency.…”

Section: Resultsmentioning

confidence: 99%

“…It is a direct approach to produce hydrocortisone (11b-OH-S, HC), which is not only a matured medical steroid but also the starting substrate for the manufacturing of several other potential steroids, such as prednisolone (i.e., 1-dehydrocortisol) [1][2][3]. Among the strains used for 11b-hydroxylation, a fungus Curvularia lunata is a very important strain [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Optimisation of Hydrocortisone Production by Curvularia lunata

Lu¹,

Du²,

Wang³

et al. 2007

Appl Biochem Biotechnol

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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%.

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“…Fungal cultures (10 day-old) on ZT (Wilmańska et al 1992) agar slants were used to prepare inoculum for 20 ml Sabouraud liquid medium (Difco). Preculturing (24h) and main incubation were carried out at 28 C on rotary shaker at 180 rpm in 100 ml Erlenmeyer flasks on Sabouraud liquid medium.…”

Section: Preculturing Of Fungal Strains and Cultivation On Sabouraud mentioning

confidence: 99%

Pentachlorophenol and spent engine oil degradation by Mucor ramosissimus

Szewczyk

Długoński

2009

International Biodeterioration & Biodegradation

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Pentachlorophenol (PCP) has been widely used for many years and belongs to the most toxic pollutants. Spent engine oils enter environment every day in many ways. Both of them cause great environmental concern. In the present work we focused on identifying metabolites of PCP biodegradation formed in cultures of Mucor ramosissimus IM 6203 and optimization of medium composition to enhance PCP removal in the presence of engine oil acting as a carbon source. Pentachlorophenol (PCP) to tetrachlorohydroquinone (TCHQ) transformation was the most interesting transformation conducted by the tested strain. TCHQ was further transformed to 2,3,5,6-TCP and 2,3,4,6-TCP. Strain IM 6203 is also capable of PCP transformation to corresponding anisoles -pentachloromethoxybenzene (PCMB) and pentachloroethoxybenzene (PCEB). Characterization of enzymatic background involved in PCP to TCHQ transformation showed that TCHQ formation is catalyzed by inductive and cytochrome P-450 dependent enzymatic system. Experiments conducted on mineral medium allowed defining the optimal quantitative and qualitative medium make-up for PCP to TCHQ transformation. Biodegradation of PCP on optimized synthetic medium X was more efficient than on rich Sabouraud medium. The t ested strain is capable of growth in the presence of spent engine oil therefore we checked the ability of PCP transformation on optimized synthetic medium containing oil as a carbon source. Collected results showed that PCP removal and TCHQ formation was th e most efficient on the oil-containing medium (OX medium). PCP removal and TCHQ forming after 240h of culturing reached 1.19 mg/l and 0.89 mg/l, respectively. Addit ionally, 55.5% of oil introduced to medium was removed during 10 days of the experiment. PCP biodegradation mechanisms used by Mucor species are still not sufficiently explained. The presented results point to the tested strain as an interesting model for the research on fungal PCP biodegradation in the areas highly contaminated with engine oil and for its future application in PCP and oils removal.

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Elimination of by-products in 11β-hydroxylation of Substance S using Curvularia lunata clones regenerated from NTG-treated protoplasts

Cited by 30 publications

References 12 publications

Enhancement of emulsifier production by Curvularia lunata in cadmium, zinc and lead presence

Enhancement of emulsifier production by Curvularia lunata in cadmium, zinc and lead presence

Optimisation of Hydrocortisone Production by Curvularia lunata

Pentachlorophenol and spent engine oil degradation by Mucor ramosissimus

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