Investigation of Catalytic Properties of Immobilized Enzymes and Cells by Flow Microcalorimetry - Advances in Biochemical Engineering Biotechnology - page 91

Table 3. Screening of immobilized biocatalysts by means of the flow microcalorimetry

Biocatalyst Form Origin Mode of immobilization Reference

Invertase Enzyme S. cerevisiae Covalent [27]

Enzyme S. cerevisiae Biospecific [30]

Enzyme S. cerevisiae Biospecific + [31]

covalent

Enzyme S. cerevisiae Biospecific [35]

D -Amino acid oxidase Enzyme T. variabilis a Cross -linking [28]

Cells T. variabilis Entrapment [28]

T. variabilis

Cells Entrapment + [28]

cross -linking

Penicillin acylase Enzyme E. coli Entrapment + [40]

cross -linking

E. coli

Cells Entrapment + [40]

cross -linking

Cells E. coli Entrapment [29]

a Trigonopsis variabilis.

3. The support matrix is reusable;
4. Oriented immobilization facilitates good expression of activity and stabiliza-
tion against inactivation;
5. Direct immobilization of the enzyme from partially pure preparations is
possible.
As an example, we have chosen the model “bioaffinity-immobilization of
glycoenzymes on lectins, precoupled on water-insoluble matrices”. The largest
and best characterized is concanavalin A (Con A), that belongs to the legume
family. Con A has been widely used in the affinity purification of a variety of
glycoenzymes and nearly exclusively in the immobilization of glycoenzymes on
a variety of supports.A good review of the use of Con A in glycoenzyme immo-
bilization has recently been published [43].
The binding of the glycoenzyme to the Con A-precoupled affinity support
may be very strong,but it is nevertheless reversible under specific conditions.
A biospecific adsorption of invertase to pre-coupled Con A is the best ex-
ample. Con A-immobilized invertase in the FMC packed bed reactor retained
full operational stability for several hours/days of processing in the flow,even
at high substrate concentration [31]. In spite of the extraordinarily strong
binding of invertase to the Con A-bead cellulose conjugate (K D = 5 10 -9 M),

conditions have been found for the use of a Con A column as an affinity
chromatography medium. The determining factor in the release of bound
invertase by a counterligand (

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-methyl- D - manno pyranoside) is the time of
incubation. This phenomenon was demonstrated in both batch and flow-
through experiments by the FMC.It was also shown that the ease of elution or

a