Inner epidermal membrane of the onion bulb scales was studied as a natural polymer support for immobilization of the glucose oxidase (GOD) enzyme for biosensor application. Onion epidermal membrane was used for immobilization of glucose oxidase and was associated with dissolved oxygen (DO) probe for biosensor reading. Glucose was detected on the basis of depletion of oxygen, when immobilized GOD oxidizes glucose into gluconolactone. A wide detection range between 22.5 and 450 mg/dl was estimated from calibration plot. A single membranewas reused for 127 reactions with retention of
~90% of its initial enzyme activity. Membrane was stable for 45 days
(~90% activity) when stored in buffer at 4 ◦C. Surface structure studies of the immobilized membranes were carried under SEM. To our knowledge, this is the first report on employing inner epidermal membrane of onion bulb scales as the solid support for
immobilization of enzyme.
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