Steroid transformation at high substrate concentrations using immobilized Corynebacterium simplex cells

  title={Steroid transformation at high substrate concentrations using immobilized Corynebacterium simplex cells},
  author={Alkis Constantinides},
  journal={Biotechnology and Bioengineering},
The steroid transformation of hydrocortisone to prednisolone, combining the two techniques of immobilized whole cells and high steroid concentrations, was investigated and found to be a feasible process. Freeze‐dried Corynebacterium simplex cells were immobilized in collagen, tanned with glutaraldehyde, and cast into a membrane. The reaction was studied at hydrocortisone concentrations ranging from 5 to 50 mg/ml. The following aspects of the system were examined: (1) the substrate concentration… 
Δ′-Dehydrogenation of steroids byArthrobacter simplex immobilized in calcium polygalacturonate beads
The operational stability of the process and the feasibility of repeated batch bioconversions was shown to be comparable to similar processes.
Steroidumwandlung mit immobilisierten Mikroorganismen
The review deals with the present scientific state of the steroid transformations performed with immobilized biocatalysts, their applications and development trends.
Steroid bioconversion in a microemulsion system
The Δ1,2‐dehydrogenation of high concentrations of the steroid ‐methyl‐Reichstein's compound S‐21‐acetate (16MRSA) in a microemulsion system was studied using heat‐dried and thawed Arthrobacter simplex cells as biocatalyst and the reaction was strongly inhibited by high product concentrations.
Some enzymatic properties of cholesterol oxidase produced by Brevibacterium sp
Cholesterol oxidation by the membrane-bound enzyme was a first order reaction type and minor no steroidal compounds as well as 4-colesten-3-one found in the reaction media arose during fermentation process and were extracted together with the enzyme in the buffer solution.
Steroid modifications with immobilized biocatalysts--use of immobilized enzyme-requiring cofactor regeneration and of immobilized mycelium.
It seems promising to apply immobilized biocatalysts to the bioconversion of hydrophobic compounds in organic solvents system.
Applications of Chemical Factors in Steroid Bioconversion
The applications of three chemical factors (growth regulator,surfactant and cyclodextrin), and their effects on steroid microbial enzymatic conversion were extensively discussed, which provides insights into the development of novel approaches to cost-effectively improve biosynthesis efficiency in steroid medicine.
Sterols Bioconversions in Systems with an Organic Phase
It was concluded that for this reaction, properties such as interfacial tensions, the molecule chain-length and presence of double bonds may influence the outcome of the enzyme activity.


A silicone polymer as a Steroid Reservoir for enzyme‐catalyzed Steroid reactions
Since steroids are only slightly soluble in the aqueous solutions in which enzymatic reactions take place, it is difficult to obtain high effective concentrations per unit reactor volume when enzymes
A new and a peculiar phenomenon caused by a microorganism concerning with steroidal fermentation and an economical process for the industrial preparation of prednisolone from hydrocortisone are reported and the name "pseudo-crystallofermentation" is proposed.
Synthesis of Organic Acids and Modification of Steroids by Immobilized Whole Microbial Cells
Investigation of reaction schemes catalyzed by collagen-whole cell complexes and whole microbial cells for immobilized whole cell systems with simple systems such as glucose isomerization which involve only a single enzymatic reaction.
Preparation and application of polymer‐entrapped enzymes and microorganisms in microbial transformation processes with special reference to steroid 11‐β‐hydroxylation and Δ1‐dehydrogenation
It was shown that gel‐cell granules which had lost part of their 11‐β‐hydroxylase activity on storage could be reactivated yielding preparations with increased activity.
Sequential 11α‐hydroxylation and 1‐dehydrogenation of 16α‐hydroxycortexolone
Two‐step microbial transformation of 16α‐hydroxycortexolone to its 1‐dehydro‐11α‐hydroxy derivative, without isolating an intermediate, was achieved with an overall yield of 72% of product at a
Spectrophotometric methods for monitoring the microbial transformation of steroids. II. Absorbance ratio spectrophotometric determination of per cent conversion of 9α‐fluoro‐16α‐hydroxyhydrocortisone to 9α‐fluoro‐16α‐hydroxyprednisolone
  • E. Ivashkiv
  • Chemistry, Biology
    Biotechnology and bioengineering
  • 1971
The absorbance ratio determination of conversion of the steroids is based on the measurement of the absorbance of aqueous steroid borate complexes at 241.5 mμ and 271 mμ.
1‐dehydrogenation of steroids by Septomyxa affinis
Dehydrogenation of steroids by Septomyxa affinis is brought about by an inducible enzyme where only soluble substrate steroid is attacked and the pH‐activity curve is shallow.
Kinetics of 1‐dehydrogenation of steroids by Septomyxa affinis
Mathematical models for the kinetics of 1‐dehydrogenation of steroids by Septomyxa affinis are considered. A model providing for product inhibition fits experimental data best. Product inhibition was