Mass transfer with reaction kinetics of the biocatalytic membrane reactor using a fouled covalently immobilised enzyme layer (α–CGTase–CNF layer)

Abstract

A dynamic mathematical model was used in this study to describe the mass transfer and reaction kinetics of a fouled α-CGTase-CNF layer in a biocatalytic membrane reactor (BMR) system. BMR performance was evaluated based on the effect of substrate concentration and pneumatic gauge pressure on the permeate flux, total permeate volume, starch conversion, and α-CD production. A model is introduced based on the layer of mass limit as the resistance blocking mechanism with reaction kinetics on the fouled α-CGTase-CNF layer. Important unknown parameters of the constants describing the layer resistance, KML0 and the kinetic constant of Michaelis-Menten, kcat, for mass transfer and its reaction kinetics, were successfully estimated at 3.9 × 107 min/mL and 216.18 mg-starch/cm3⋅U⋅min, respectively, using the proposed models. The study found that the kcat value corresponding to the maximum efficiency of the enzyme on starch cyclisation was a critical parameter in the prediction of the BMR dynamic profiles. Thus, the proposed model in this study can be used for further development of the BMR system, with excellent hydrodynamic and reaction performance.

Economical synthesis of γ-cyclodextrin catalyzed by oriented cyclodextrin glycosyltransferase displayed on bacterial polyhydroxyalkanoate nanogranules

“…This finding can be attributed to the favorable interaction between the carrier and the enzyme, resulting in enzyme folding into the optimum conformation on the surface of the PHA granules, thus increasing the enzyme activity [ 21 , 23 ]. Furthermore, the γ-CGTase-PHA nanobiocatalyst was found to possess a considerable specific activity of 347.9 U/g beads (dry weight), considerably higher than that of other immobilized CGTases reported in most recent studies, such as glyoxyl–agarose immobilized CGTase (27.38 U/g support) [ 13 ], cellulose nanofiber immobilized CGTase (159.34 U/g support) [ 14 ], and glutaraldehyde pre-activated silica immobilized CGTase (101.73 U/g support) [ 35 ]. This finding is likely because PhaC dictates a homogenous orientation of its fusion partner on the nanobeads’ surface, hence providing a maximum interaction with substrates and increased accessibility to substrates, leading to high specific activity of the immobilized enzymes if properly engineered [ 22 , 36 ].…”

Optimized Production of Glucose Syrup and Enzyme Membrane Reactor Using In Situ Product Recovery

“…1,39,40 Immobilized enzymes are less active than free enzymes, and typically exhibit a wide-range activity of 5%−80% depending on the form of enzyme immobilization, i.e., physical or chemical. 1,7,39,41 The loss of activity in the immobilized enzyme is due to the structural distortions in the enzyme, which result from binding to the solid surface of the membrane pores. 39 The fouling mechanism can be considered as an advantage for the immobilization of enzymes, as long as the limitations of mass transfer and the decrease in flux through the membrane can be kept to a minimum.…”

“…39 The fouling mechanism can be considered as an advantage for the immobilization of enzymes, as long as the limitations of mass transfer and the decrease in flux through the membrane can be kept to a minimum. 7,41 4. CONCLUSIONS An enzyme membrane reactor was developed in an ISPR system for the optimal recovery of the components present in starch.…”