Film diffusional influences on the kinetic parameters in packed‐bed immobilized enzyme reactors

Patwardhan, V.S.; Karanth, N. G.

doi:10.1002/bit.260240402

Cited by 33 publications

(7 citation statements)

References 33 publications

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“…The higher apparent resistance to thermoinactivation of PANIS, and PARIS, is probably partly an artefact resulting from a substrate diffusional limitation effect. [27][28][29] This observation is in agreement with the relative activity observed for the different compounds ( Table 3). Moreover, PANIS, and PARIS, (Fig.…”

Section: Heat Inactivationsupporting

confidence: 91%

Characterization of a chemically modified β‐amylase immobilized on porous silica

Germain

Crichton

1988

J of Chemical Tech & Biotech

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β‐Amylase was coupled to a periodate oxidized dextran by reductive alkylation in the presence of sodium cyanoborohydride. The loss of activity (57%) during the cross‐linking of the enzyme was the result of steric hindrance near the catalytic site. In order to verify this hypothesis, the residual activity was determined with substrates of variable molecular size. The residual activity was inversely proportional to the particulate size of the substrate. Increases in residual activity, of up to 53% were obtained using an orientated chemical modification in the presence of a substrate which protects the catalytic site. Native and dextran‐conjugated β‐amylase were immobilized on an amino activated silica by a classical method using glutaraldehyde for the native enzyme and by reductive alkylation for the modified enzyme. The relative activity of the enzymes obtained after this insolubilization was very high for the modified amylase, 45% for a medium enzyme concentration, compared with 4% at the same concentration for the native enzyme. This difference can be attributed to the variation of the length of the space arm between the silica and the enzyme. The soluble β‐amylase dextran conjugate had a superior thermoresistance to that of the native enzyme; its optimal temperature of activity was 5°C higher than that of the native enzyme. This stabilization may be attributable to a rigidification of the protein structure. Immobilization of both native and modified enzymes on a amino silica resulted in thermostabilization of the enzymes. The optimal temperature of activity was 70°C for the native immobilized β‐amylase (some 10°C higher than that of the native enzyme) and 75°C for the chemically modified, and subsequently immobilized, β‐amylase. The immobilized forms of the enzymes were used for 14 days at 55°C in continuous substrate processing. The greater eflciency of the chemically modified β‐amylase was demonstrated by a four‐fold increase in maltose production compared to the classical method of immobilization. A kinetic study confirmed the stabilization of the β‐amylase by a reduction of the rate constant of inactivation of the different modified enzymes.

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Section: Heat Inactivationsupporting

confidence: 91%

Characterization of a chemically modified β‐amylase immobilized on porous silica

Germain

Crichton

1988

J of Chemical Tech & Biotech

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“…For a given reactor-inlet substrate concentration and liquid Ñow rate, was calculated by eqn k L a (22). Using this value, was calculated and then / E inserted into eqns (11) and (12), which gave and V m app After substitution of these values, eqn (13) (19). This indicates the validity of a series of equations for the apparent kinetic parameters presented here.…”

Section: Numerical Calculation Methodsmentioning

confidence: 55%

A Film Diffusional Effect on the Apparent Kinetic Parameters in Packed-Bed Immobilized Enzyme Reactors

Miyakawa

Shiraishi

1997

J. Chem. Technol. Biotechnol.

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A film diffusional effect on the apparent kinetic parameters in packed‐bed reactors containing the enzyme immobilized on the surface of a nonporous support was investigated. A comparison of the plug‐flow reactor model equation, expressed analytically in terms of the apparent kinetic parameters, with experimental data showed that the conventional linearized plot based on the reactor model equation was essentially nonlinear. Simulations for the apparent kinetic parameters were made using the intrinsic kinetic parameters and volumetric mass‐transfer coefficient previously determined from experimental data. Consequently, the apparent kinetic parameters were found to decrease monotonically with the increase of liquid flow rate. On the other hand, with the increase of reactor‐inlet substrate concentration, these constants first increased, passed through a maximum, and finally decreased toward their respective intrinsic values. © 1997 SCI.

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“…The solid line in Figure 1 represents the true relationship obtained from the exact equation [see ref. 7, eq. (16)l.…”

Section: Theorymentioning

confidence: 99%

Film resistances in packed‐bed immobilized enzyme reactors: A reassessment of the kinetic plots

Karnath

Patwardhann

1982

Biotech & Bioengineering

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Film diffusional influences on the kinetic parameters in packed‐bed immobilized enzyme reactors

Cited by 33 publications

References 33 publications

Characterization of a chemically modified β‐amylase immobilized on porous silica

Characterization of a chemically modified β‐amylase immobilized on porous silica

A Film Diffusional Effect on the Apparent Kinetic Parameters in Packed-Bed Immobilized Enzyme Reactors

Film resistances in packed‐bed immobilized enzyme reactors: A reassessment of the kinetic plots

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