Combinatorial biocatalysis: taking the lead from Nature

Altreuter, David H.; Clark, Douglas S.

doi:10.1016/s0958-1669(99)80022-6

Cited by 53 publications

(28 citation statements)

References 23 publications

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“…Examples of practical applications are enantioselective synthesis [7], chiral resolution [8] and combinatorial biocatalysis [9]. The possibility of the solubilization of hydrophobic substrates or products in organic solvents opens opportunities for the enzymatic production of poorly water soluble fine chemicals and pharmaceuticals.…”

Section: Introductionmentioning

confidence: 99%

Activation of subtilisin Carlsberg in hexane by lyophilization in the presence of fumed silica

Würges

Pfromm

Rezac³

et al. 2005

Journal of Molecular Catalysis B: Enzymatic

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Subtilisin Carlsberg (SC) was lyophilized from an aqueous buffer solution containing different amounts of unmodified commercial fumed silica. The activity of the enzyme/fumed silica preparation in hexane was compared to pure freeze-dried enzyme, and to a freeze-dried preparation reported in the literature with potassium chloride as additive. A sharp increase in enzyme activity was found to correlate with an increasing amount of fumed silica added to the enzyme solution prior to freeze-drying. A weight-ratio of 98.5wt% fumed silica relative to the mass of the final enzyme/fumed silica preparation led to about 130 fold increased activity of SC in hexane (when compared to pure lyophilized SC in hexane). This is about twice the activation effect compared to including potassium chloride in the buffer solution before freeze-drying [1].When freezing at -20ºC instead of in liquid nitrogen, even better activation was observed with fumed silica. We hypothesize that the activation of SC in hexane by immobilization of the enzyme on fumed silica is likely due to the distribution of the enzyme on the large surface area of fumed silica. This alleviates mass transfer limitations.

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Section: Introductionmentioning

confidence: 99%

Activation of subtilisin Carlsberg in hexane by lyophilization in the presence of fumed silica

Würges

Pfromm

Rezac³

et al. 2005

Journal of Molecular Catalysis B: Enzymatic

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“…After the initial optimization, we have attempted the stereoselective cyclization reaction with many 1-tetralone-derived bis-hydroxymethylated compounds and mono-hydroxymethylated compounds (1,(4)(5)(6)(7)(8)(9)(10) with NIS as a halogen source with Bz 2 O as a radical initiator in CCl 4 as solvent. The results are summarized in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…[4] These efforts also have led to significant advances in novel strategies in synthetic organic chemistry. [4][5][6][7] The progress made has paved the way for the integration of natural product-inspired compound collections into medicinal chemistry and chemical biology research. Enantioselective desymmetrization (ED) is such a unique class of reactions and belongs to the field of asymmetric synthesis; a maximum yield of 100% of the product can be obtained by applying this strategy.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Desymmetrization of 2,2‐Bishydroxymethyl‐1‐tetralones by Iodocyclization, Synthesis of Novel Enantiopure [6.6.5] Tricyclic Framework and Chemoenzymatic Diversity Generation

2011

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Stereoselective halocyclization of prochiral 2,2-bishydroxymethyl-1-tetralone derivatives with N-halosuccinamides afforded an interesting tricyclic scaffold found in many naturally occurring hasubanan alkaloids. Enantiopure tricyclic scaffolds are synthesized by using enzymatic kinetic resolution (EKR) of the parent racemic compound. Microbial ketoreductase (Geotrichum candidum, Aspergillus niger and Candida parapsilosis) mediated stereoselective reduction reactions have been successfully employed to these enantiopure tricyclic scaffolds which, followed by functional group manipulation, provides novel cyclic frameworks.

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“…[1][2][3] An excellent review and outlook for enzymatic catalysis in solvents is available. 4 Enzymes are renewable catalysts, and they exhibit a wide array of attractive reactivities and selectivities in nonaqueous solvents 2,3,[5][6][7][8][9] that are often not accessible in water. The thermal and storage stability of enzymes can be significantly enhanced in nonaqueous solvents.…”

Section: Introductionmentioning

confidence: 99%

Fumed silica activated subtilisin Carlsberg in hexane in a packed‐bed reactor

Pfromm¹,

Rezac²,

Würges³

et al. 2006

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Enzymatic catalysis in organic solvents can enable applications, reactivities, and selectivities that are not accessible in water. The use of enzymes for catalysis in organic solvents has been somewhat hampered by their relatively low-catalytic activity. A new preparation of the enzyme subtilisin Carlsberg (SC) with fumed silica as support (FS) has been developed. This preparation matches and sometimes exceeds the activity of some of the best reported preparations of the same enzyme for use in solvents. The usefulness of our preparation in a packed-bed reactor is explored here. The catalytic characteristics of our preparation containing 5 wt % of enzyme/95 wt % FS in a packed-bed reactor for a model transesterification in hexane is determined. Mass-transfer limitations are explored, and a comparison to batch results is given. The activity of our preparation after prolonged storage as a packed bed is investigated. Our immobilized enzyme preparation may be a step towards more economical enzymatic catalysis in organic solvents.

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Combinatorial biocatalysis: taking the lead from Nature

Cited by 53 publications

References 23 publications

Activation of subtilisin Carlsberg in hexane by lyophilization in the presence of fumed silica

Activation of subtilisin Carlsberg in hexane by lyophilization in the presence of fumed silica

Stereoselective Desymmetrization of 2,2‐Bishydroxymethyl‐1‐tetralones by Iodocyclization, Synthesis of Novel Enantiopure [6.6.5] Tricyclic Framework and Chemoenzymatic Diversity Generation

Fumed silica activated subtilisin Carlsberg in hexane in a packed‐bed reactor

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