The enzymatic transformation of water-insoluble reactants in nonaqueous solvents. Conversion of cholesterol to cholest-4-ene-3-one by a Nocardia sp.

Buckland, BC; Dunnill, P.; Lilly, M. D.

doi:10.1002/(sici)1097-0290(20000320)67:6<714::aid-bit9>3.3.co;2-8

Cited by 7 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This led to the development of biocatalysis in biphasic systems involving organic solvents (Buckland et al 1975;Leon et al 1998). The discovery of solvent-tolerant bacteria led to whole cells becoming commercially viable as biocatalysts in these environments (De Bont 1998).…”

Section: Introductionmentioning

confidence: 99%

The bioreduction of a β-tetralone to its corresponding alcohol by the yeastTrichosporon capitatumMY1890 and bacteriumRhodococcus erythropolisMA7213 in a range of ionic liquids

Hussain

Pollard

Lye

2007

Biocatalysis and Biotransformation

View full text Add to dashboard Cite

The stereospecific reduction of 6-Br-b-tetralone to its corresponding alcohol (S)-6-Br-b-tetralol was carried out by the yeast Trichosporon capitatum MY1890 and by the bacterium Rhodococcus erythropolis MA7213, using a range of ionic liquids chosen for the diversity of their composition. The decrease in cell viability of both types of cell upon exposure to ionic liquids was found to be between that determined for cells residing purely in fermentation media, and cells residing in a twophase mixture of media and organic solvent (toluene). For T. capitatum MY1890 bioconversions, the water-miscible hydrophilic ionic liquid [Emim][TOS] gave a reaction profile comparable to that observed in the previously studied waterÁ ethanol (10% v/v) system, in terms of overall rate of reaction (0.2 g (prod) L (1 h (1 ) and conversion (100%). Of the hydrophobic ionic liquids evaluated, [Oc 3 MeN][BTA] gave the best conversion of 60%, but at a much reduced rate, suggesting solute mass transfer from the ionic liquid phase was rate-limiting. For bioconversions carried out with R. erythropolis MA7213 employing 20% v/v [Emim][TOS] as a co-solvent, the conversion yield doubled, and a fourfold increase in initial rate was found compared to the standard ethanol co-solvent. This was attributed to improved cell viability and reduced aggregation of the R. erythropolis MA7213 compared to T. capitatum MY1890. Overall, this study demonstrates the feasibility of using ionic liquids for whole cell biocatalysis; however, no obvious link is apparent between the physico-chemical properties of ionic liquids, their influence on cell viability, and their efficacy as media for bioconversions.

show abstract

Section: Introductionmentioning

confidence: 99%

The bioreduction of a β-tetralone to its corresponding alcohol by the yeastTrichosporon capitatumMY1890 and bacteriumRhodococcus erythropolisMA7213 in a range of ionic liquids

Hussain

Pollard

Lye

2007

Biocatalysis and Biotransformation

View full text Add to dashboard Cite

show abstract

“…Buckland et al [9] reported the formation of 7 g/h cholestenone using 100 g of Nocardia cells in 200 mL of carbon tetrachloride containing 16% (w/v) cholesterol, at 20 • C, while Liu et al [10] reported that 94.6% of added cholesterol could be converted to cholestenone by the 6 g wet cells of Arthrobacter in 300 mL aqueous/carbon tetrachloride two-phase system containing 10% (w/v) cholesterol at 30 • C. Marques et al [11] reported a conversion yield of 67% of cholesterol (1 g/L) within a microchannel reactor at a fluid flow rate of 14 L/min in an enzyme based biotransformation process. Considering the results obtained through the present investigation it may be inferred that there is a scope of increasing the product yield by increasing the quantity of enzyme immobilized beads and cholesterol concentration in the reaction medium.…”

Section: Biotransformation Of Cholesterol To Cholestenonementioning

confidence: 99%

“…This ketosteroid also has anti-obesity effect thus depicting its potential as food additive or medicine for preventing obesity related diseases [8]. Cholestenone is generally produced through biotransformation route using microbial cells as catalysts [9,10] with limited report where enzyme has been also used as catalyst [11]. A variety of microorganisms produce cholesterol oxidase, among which Rhodococcus species have attracted wide attention for their high production capability of the enzyme [3,4,12].…”

Section: Introductionmentioning

confidence: 99%

Application of chitosan beads immobilized Rhodococcus sp. NCIM 2891 cholesterol oxidase for cholestenone production

Ahmad¹,

Goswami²

2014

Process Biochemistry

View full text Add to dashboard Cite

“…The third technological advance was the development of techniques for biocatalysis in organic media. The usage of very high proportions of organic solvents to increase the solubility of reactants was examined in 1975 for the reaction with isolated cholesterol oxidase to produce cholestenone [90]. The enzymatic synthesis was believed to be incompatible with most organic syntheses carried out in non-aqueous media.…”

Section: From Wine Bottle To a State-of-the-art Facility -The Historymentioning

confidence: 99%

History of Industrial Biotransformations – Dreams and Realities

Vasić-Rački

2006

Industrial Biotransformations

View full text Add to dashboard Cite

Throughout the history of mankind, microorganisms have been of enormous social and economic importance. Without even being aware of their existence, very early on in history man was using them in the production of food and beverages. The Sumerians and Babylonians were practising the brewing of beer before 6000 BC, references to wine making can be found in the Book of Genesis and the Egyptians used yeast for baking bread. However, knowledge of the production of chemicals such as alcohols and organic acids through fermentation is relatively recent and the first reports in the literature only appeared in the second half of the 19th century. Lactic acid was probably the first optically active compound to be produced industrially by fermentation. This was accomplished in the USA in 1880 [1]. In 1921, Chapman reviewed a number of early industrial fermentation processes for organic chemicals [2].In the course of time, it was discovered that microorganisms could modify certain compounds by simple, chemically well defined reactions, which were further catalyzed by enzymes. Nowadays, these processes are called "biotransformations". The essential difference between fermentation and biotransformation is that there are several catalytic steps between the substrate and the product in a fermentation while there are only one or two in a biotransformation. The distinction is also in the fact that the chemical structures of the substrate and the product resemble one another in a biotransformation, but not necessarily in a fermentation.

show abstract

The enzymatic transformation of water-insoluble reactants in nonaqueous solvents. Conversion of cholesterol to cholest-4-ene-3-one by a Nocardia sp.

Cited by 7 publications

References 6 publications

The bioreduction of a β-tetralone to its corresponding alcohol by the yeastTrichosporon capitatumMY1890 and bacteriumRhodococcus erythropolisMA7213 in a range of ionic liquids

The bioreduction of a β-tetralone to its corresponding alcohol by the yeastTrichosporon capitatumMY1890 and bacteriumRhodococcus erythropolisMA7213 in a range of ionic liquids

Application of chitosan beads immobilized Rhodococcus sp. NCIM 2891 cholesterol oxidase for cholestenone production

History of Industrial Biotransformations – Dreams and Realities

Contact Info

Product

Resources

About