Preparation of Aldolase Biocatalysts

Most organisms contain aldolases and more than 30 of such enzymes are known already. Class I aldolases occur mainly in higher eukaryotes. Nevertheless, there is a variety of class I enzymes found in prokaryotes. On the other hand, class II aldolases are present in prokariotes and lower eukariotes. 

DHAP-dependent aldolases constitute the most important group concerning bio-catalytic applications. Until now, class I fructose-1,6-bisphosphate aldolase from 

The four DHAP-dependent aldolases have been obtained from microbial and animal sources, determined their sequence, and cloned and overexpressed in Escherichia coli (Fessner et al. 1991 Henderson et al. 1994 Garcia-Junceda et al. 1995). DERA has also been found in microorganisms and cloned in E. coli (Chen 

After recovery of biomass by centrifugation, aldolase-containing cell lysates are obtained by mechanical or ultrasound cell disruption. A purification procedure is usually required to prepare a pure catalyst for synthetic purposes and to avoid the presence of any enzyme producing undesirable side-reactions. Usually, aldolases are purified from cell lysates by a combination of conventional purification steps gel filtration, ammonium sulphate precipitation, ionic exchange chromatography. 

Enzyme immobilization allows a wider use of enzymes in fine chemistfy because it facilitates catalyst reuse and downstream processing of the product and, sometimes, it improves enzyme stability. In spite that enzyme immobilization techniques have been used widely during the last 30 years, very few information can be found about aldolases immobilization. 

---