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- Larsson, P O, et al.
(författare)
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New Approach to Steroid Conversion Using Immobilised Microorganisms
- 1976
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 263:5580, s. 796-797
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Tidskriftsartikel (refereegranskat)abstract
- The marked increase in demand for contraceptives and anti-inflammatory agents such as cortisol and prednisolone, combined with a diminishing supply of steroid raw materials may lead to shortages of steroid drugs1. Thus it is important to develop new sources for steroids as well as to devise more efficient means for steroid conversions. Here we report a new approach to steroid transformation in which activated immobilised microorganisms are utilised and which represents a promising alternative to conventional microbial transformation processes.
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| 2. |
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| 5. |
- Ohlson, Sten, et al.
(författare)
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Steroid Transformation by Activated Living Immobilized Arthrobacter Simplex Cells
- 1978
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Ingår i: Biotechnology and Bioenginering. - : Wiley. - 0006-3592 .- 1097-0290. ; 20:8, s. 1267-1284
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Tidskriftsartikel (refereegranskat)abstract
- A preparation of living Arthrobacter simplex cells immobilized in polyacrylamide gel, which showed steroid-Δ1-dehydrogenase activity, was studied. The entrapped microorganisms catalyzed the transformation of cortisol to prednisolone and this reaction was followed spectrophotometrically or with the aid of thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). About 40% of the original activity found with free bacteria was retained after immobilization. The steroid dehydrogenase activity of polyacrylamide-entrapped A. simplex could be raised to a minor extent in alcoholic solvents or by addition of a cofactor such as menadione. On incubation in various nutrient media, on the other hand, the activity could be increased considerablyl, usually 7–10 times. Possible causes for the observed increase in activity have been investigated, and microbial growth of the original entrapped microorganisms appears to be the major reason. Frozen activated preparations of immobilized A. simplex showed only a small loss of activity on storage for at least four months. A semicontinuous batch wise operation with immobilized A. simplex in different nutrient media was carried out. At the end of the experiment the steroid transformation capacity was 0.5 g steroid per day per g gel (wet weight).
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| 6. |
- Ohlson, Sten, et al.
(författare)
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Steroid Transformation by Living Cells Immobilized in Calcium Alginate
- 1979
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Ingår i: European Journal of Applied Microbiology and Biotechnology. ; 7, s. 103-110
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Tidskriftsartikel (refereegranskat)abstract
- Whole cells of Arthrobacter simplex were immobilized in a living state in calciumalginate gel. The bacteria showed steroid-1-dehydrogenase activity and the production of prednisolone from cortisol was investigated. The 1-dehydrogenase activity of the immobilized cells could be increased about ten-fold by incubation in nutrient media (e.g., containing 0.5% peptone abd 0.2% glucose). The reason for this activation was examined and it was found that the immobilized cells were capable of multiplying when supplied with nutrients. Furthermore, provided that an inducer, cortisol, was present, the steroid-1-dehydrogenase activity increased in proportion to the increase in the number of cells and it was thus concluded that microbial growth was the cause of activation. Experiments on repeated, batch-wise pseudocrystallofermentation with immobilized A. simplex cells also showed that immobilized cells could be advantageously used for pseudocrystallofermentation of steroids.
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