Identification of catalytically important residues of the carotenoid 1,2-hydratases from Rubrivivax gelatinosus and Thiocapsa roseopersicina

Carotenoid 1,2-hydratases (CrtC) catalyze the selective addition of water to an isolated carbon–carbon double bond. Although their involvement in the carotenoid biosynthetic pathway is well understood, little is known about the mechanism by which these hydratases transform carotenoids such as lycopene into the corresponding hydroxyl compounds....

On the Michael addition of water to C = C bonds

?-Hydroxy carbonyl compounds are an important class of compounds often found as a common structural motif in natural products. Although the molecules themselves look rather simple, their synthesis can be challenging. Water addition to conjugated C = C bonds opens up a straightforward route for the preparation of ?-hydroxy carbonyl compounds....

Novel approaches for using dehydrogenases and ene-reductases for organic synthesis

Oxidation of alcohols is a reaction of major interest for organic chemistry. However, the most common chemical routes developed so far involve the use of toxic or hazardous reagents or catalysts that often lack good chemoselectivity. In this respect, alcohol dehydrogenases (ADHs) represent a very valuable biocatalytic alternative, as they can...

Enantioselective Michael Addition of Water

The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important ?-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent...

Draft genome sequence of Rhodococcus rhodochrous strain ATCC 17895

Rhodococcus rhodochrous ATCC 17895 possesses an array of mono- and dioxygenases, as well as hydratases, which makes it an interesting organism for biocatalysis. R. rhodochrous is a Gram-positive aerobic bacterium with a rod-like morphology. Here we describe the features of this organism, together with the complete genome sequence and annotation....

Transformation of biomass into commodity chemicals using enzymes or cells

Towards recyclable NAD(P)H regeneration catalysts

Rh(III)-TsDPEN, an immobilized analog of the well-known [Cp*Rh(bpy)(H2O)]2+ was evaluated as a heterogeneous, recyclable regeneration catalyst for reduced oxidoreductase cofactors [NAD(P)H]. Repeated use of this catalyst was established and the catalytic properties were initially investigated. Apparently, Rh(III)-TsDPEN is prone to severe...

Enzyme Initiated Radical Polymerizations

Biocatalysis is propagating into practically every area of organic chemistry, amongst them radical polymerizations. A review of the recent developments of this dynamic and quickly evolving area of research is presented together with a critical evaluation of its potential to yield novel polymers and/or environmentally more benign synthetic...

Biochemical characterization of the carotenoid 1,2-hydratases (CrtC) from Rubrivivax gelatinosus and Thiocapsa roseopersicina

Two carotenoid 1,2-hydratase (CrtC) genes from the photosynthetic bacteria Rubrivivax gelatinosus and Thiocapsa roseopersicina were cloned and expressed in Escherichia coli in an active form and purified by affinity chromatography. The biochemical properties of the recombinant enzymes and their substrate specificities were studied. The purified...

Development of a monolithic bioreactor: Design and application

Recently, biocatalysis has become an interesting alternative for conventional industrial processes. Enzyme reactions are highly selective and fast, and can be performed under ambient conditions. A drawback of the use of enzymes is their fragile nature. Stirring, high temperature, or solvents can cause deactivation. Also separation of the free...

Lipase- and protease-catalyzed transformations with unnatural acyl acceptors