Investigation of Catalytic Properties of Immobilized Enzymes and Cells by Flow Microcalorimetry - Advances in Biochemical Engineering Biotechnology - page 78

Table 1. Immobilized biocatalysts studied by the flow microcalorimetry

Enzyme Immobilization technique Mathematical model Ref.

Urease Covalent bond on CPG Particle mass transfer,product [25]

inhibition kinetics,integral
packed bed

Invertase Covalent bond on bead No particle mass transfer, [27]

cellulose substrate inhibition kinetics,

differential packed bed

Co -immobilized Covalent bond to CPG Particle mass transfer, [26]

Glucose product inhibition kinetics,

oxidase-Catalase integral packed bed

Invertase Covalent bond to Qualitative observations without [33]

porous silica mathematical description

D -Amino acid a) Cells entrapped in Particle mass transfer,first-order [28]

oxidase Ca-pectate gel kinetics,differential packed bed

b) Cells entrapped in [28]

polyacrylamide gel

Invertase Biospecific adsorption No particle mass transfer, [30,31]

adsorption on Con substrate inhibition

A-bead cellulose kinetics,differential packed bed

Penicillin Cells entrapped in Particle mass transfer,substrate [29]

acylase calcium pectate gel inhibition kinetics,differential

packed bed

5.1.1
Conversion of Thermometric Data

The mathematical treatment of FMC data can be accomplished by standard pro-
cedures via the solution of mass balance equations, on condition that the data
were converted to reaction rate data with Eq. (21). As mentioned above, this
requires the determination of the transformation parameter

.Two approaches
based on calibration were developed and tested. In the first approach, thermo-
metric signals are combined with the absolute activity of IMB, which had been
determined by a separate measurement using an independent analytical techni-
que. Figure 5 shows a calibration for the cephalosporin C transformation cata-
lyzed by D -amino acid oxidase. The activity of the IMB was determined by the
reaction rate measurement in a stirred-tank batch reactor.The reaction rate was
determined as the initial rate of consumption of cephalosporin C monitored by
HPLC analysis.The thermometric response was measured for each IMB packed
in the FMC column, and plotted against the corresponding reaction rate. From
the calibration results shown in Fig. 5 it can be concluded,independently of the
type of immobilized biocatalyst,that the data fall to the same line and that there
is a linear correlation between the heat response and the activity of the catalyst
packed in the column. The transformation parameter

a

a was determined from