Ionic whole-cell biotransformation

We conclude that hydrophobic ionic liquids are promising and attractive replacements for molecular solvents in whole-cell biotransformations. 

Pfruender H, Amidjojo M, Kragl Lf et al (2004) Efficient whole-cell biotransformation in a biphasic ionic liquid/water system. Angew Chem Int Ed 43 4529-4531... 

Braiitigam, S., Bringer-Meyer, S., and Weuster-Botz, D. (2007) Asymmetric whole cell biotransformations in biphasic ionic liquid/water-systems by use of recombinant Escherichia coli with intracellular cofactor regeneration. Tetrahedron As mmetr/, 18,1883-1887. 

The enzyme may be dissolved in a mixed aqueous-ionic liquid medium, which may be mono- or biphasic or it could be suspended or dissolved in an ionic liquid, with little or no water present. Alternatively, whole cells could be suspended in an ionic liquid, in the presence or absence of a water phase. Mixed aqueous-organic media are often used in biotransformations to increase the solubility of hydrophobic reactants and products. Similarly, mixed aqueous-ionic liquid media have been used for a variety of biotransformations, but in most cases there is no clear advantage over water-miscible organic solvents such as tert-butanol. 

An important number of organic reactions are now catalyzed by whole cells or isolated enzymes. However, there are still problems associated with the solubility, yield and selectivity of these biotransformations. Ever since the solubilization of alkaline phosphatase in a mixture of [Et3NH][N03] and water (4 1), it has been known that enzymes can be stable in ionic liquids. Recent research shows that ionic liquids can be used efficiently as a medium for biocatalytic processes. ... 

Wood, N., Ferguson, J. L., Nimal Gunaratne, H. Q., Seddon, K. R., Goodacre, R., Stephens, G. M. Screening ionic liquids for use in biotransformations with whole microbial cells. Green Chemistry 2011,13,1843-1851. 

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