Reaction Techniques for Enzymes in Organic Solvent

The same reactors can be used for dealing with immobilized enzymes in organic solvents or with one-phase organic systems as for dealing with enzymes in aqueous solutions. For one-phase systems, the enzyme may be recovered from the solution by means of membrane filtration. Suspended enzyme particles may be retained in a slurry reactor (compare to Fig. 7-35) by microfiltration membranes or stainless steel sieves, whereas in other cases such as reverse micelles, ultrafiltration membranes have to be used 891. For some years ultrafiltration membranes have been available 

In foe latter case, the two phases are separated by a hydt ophohk ot liydtophilic membrane (solid supported interface). The engynie is soluble in the-aqueous phase and substrate is added up to its maximum solubility in foe aqueous phase. Substrates and. products are distributed according to their hydrophilic or hydro-phobic properties. Use membrane axes has to be large enough to avoid mass transfer limitations. High membrane areas may he achieved fey Hat membrane stacks or fey hollow fiber modules. 

If lipases am used they may be adsorbed at the interface on a hydrophobic membrane. Such a system has beets developed by Sepracor, USA, fotfoietetentiose-lective hydrolysis of racemic esters fig, ) and is used by Tmabfi Sfoyaku Co. for the kinetic resolution of 3- 4.mefoaK q)heHyl gI ccidte acid methyl ester, which is an intermediate in the synthesis of d3tternros Km 1 fo. 

Here the racemate is circulated on qtfe side of the tnpmfefane while the water necessary for hydrolysis is picked up from the other side. The resulting acid is extracted into the aqueous phase, where the pH is kept constant with, JifoOH- The enzyme is adsorbed In foe pores of foe membrane, for the pilot. scale production foe following data Were obtained reactor produefority 125 g d -nt h enzyme consumption 27 g per kg product, eaantkmierkt excess of product 95%, product yield 4 %  

Additional reactor systems, especially reactors for synthesis of oieockemkals are Surnmarteed in 99.  

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