Biocatalytic processes

Generally, there are three ways to use organic solvents or ionic liquids in a biocatalytic process ... 

Several reaction types and functional group transformations will be outlined in the following sections with a major emphasis on those biocatalytic processes of major impact on enantioselective synthesis and chiral product preparation. 

Why are enzymatic catalysts often much more efficient than other catalysts Give some examples of industrially applied biocatalytic processes. 

Cost evaluation based on mass balancing results in clearly lower cost indices for the biocatalytic process as compared to the chemical catal)d ic process (Figure 5.6). For three of the substances of the chemical procedure (Jacobsen catalyst (catalyst), 4-phenylpyridine... 

The development of the two-liquid phase biocatalytic processes requires the knowledge of different phenomena and problems that are not necessarily encountered in monophase aqueous media [40]. 

In addition to the enzyme s amino acid sequence, other parameters can affect the outcome of a biocatalytic process. For instance, a similar outcome in the aforementioned DERA-catalyzed statin synthesis was achieved by process improvements [21]. Using a thermostable variant of DERA (thermostability generally correlates well with tolerance to high concentrations of organic reagents or cosolvents), and fed-batch conditions, an efficient process that overcame sensitivity to high concentrations of chloroacetaldehyde was developed. 

In a study aim to develop biocatalytic process for the synthesis of Kaneka alcohol, apotential intermediate for the synthesis of HMG-CoA reductase inhibitors, cell suspensions of Acine-tobacter sp. SC 13 874 was found to reduce diketo ethyl ester to give the desired syn-(AR,5S)-dihydroxy ester with an ee of 99% and a de of 63% (Figure 7.4). When the tert-butyl ester was used as the starting material, a mixture of mono- and di-hydroxy esters was obtained with the dihydroxy ester showing an ee of 87% and de of 51% for the desired, sy -(3/t,5,Sr)-dihydroxy ester [16]. Three different ketoreductases were purified from this strain. Reductase I only catalyzes the reduction of diketo ester to its monohydroxy products, whereas reductase II catalyzes the formation of dihydroxy products from monohydroxy substrates. A third reductase (III) catalyzes the reduction of diketo ester to, vv -(3/t,55)-dihydroxy ester. 

Typically, a biocatalytic process for oil refining involves several stages beginning with biocatalyst production. This involves growth of the microorganism via fermentation... 

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