(516f) Development Of Microelectrochemical Biosensors For Application In Biocatalysis

Biocatalysis has always been on the forefront of biochemical engineering in terms of environmental friendliness, better selectivities and higher conversions. Many biocatalytic processes of industrial significance require cofactor as a mediator. But use of these cofactors in large quantities is not economically viable and regeneration of these cofactors is a must to obtain higher turnover number and selectivity. The research work outlines the design, development and application of a new class of microelectrochemical biosensor (MEBS) for the in situ regeneration of enzyme cofactors in conversion of pyruvate to l-lactate model system. Novel class of micro devices are constructed using microfabrication techniques to provide structurally well-defined microchannels which are used to detect biochemical reagents, such as enzyme cofactors, using voltammetric techniques.

Electrochemical characterisation of various cofactors using different electrode material was carried out and boron doped diamond electrode was found to be most biocompatible in terms of good response and resistant to deactivation due to fouling. Hydrodynamic system was then developed using BDD as a working electrode and microfabrication techniques like photolithography and soft lithography. The transport limited current was observed to follow similar trend as the theoretical one (Levich Analysis). Studies were also carried out to determine the effect of multicomponent system on cofactors. Hydrodynamic focusing technique was then applied to obtain higher conversions and reduce the amount of reactant used. Simulations obtained for such systems showed a similar trend and were used to further modify the cell design. Effect of lead in length inside the microchannel and premixing was studied using the simulations. Research is further being carried out using confocal analysis to determine the extent of diffusion of reactant stream into the focusing buffer stream.