JNTU B.Pharmacy III PHARMACEUTICAL BIOTECHNOLOGY Previous Question Paper (July - 2021 - R17)

Enzyme immobilization is the process of confining enzyme molecules to a distinct phase from the bulk solution, where the substrate and product are moved to and from the enzyme. This technique prevents the enzyme from being lost in the reaction mixture, allowing for its recovery and reuse, which significantly reduces the cost of industrial biocatalytic processes.

The primary methods of immobilization include:

1. Adsorption: Enzymes are attached to the surface of inert carriers (e.g., activated carbon, alumina) via weak physical forces like van der Waals forces or hydrogen bonding.
2. Covalent bonding: Enzymes are linked to a support matrix through strong chemical bonds, typically involving functional groups like amino or carboxyl groups on the protein surface and the support material.
3. Entrapment: Enzymes are physically trapped within the lattice of a polymer matrix (e.g., polyacrylamide gel or alginate beads) that allows substrate diffusion but prevents enzyme leakage.
4. Cross-linking: Enzymes are linked to each other using bifunctional reagents like glutaraldehyde, forming a three-dimensional insoluble aggregate.

The applicability of immobilized enzymes is vast in the pharmaceutical and food industries due to improved stability and operational efficiency. Key examples include:

• Production of 6-APA: Immobilized penicillin acylase is used for the semi-synthetic production of penicillins.
• High Fructose Corn Syrup (HFCS): Immobilized glucose isomerase is used to convert glucose to fructose on a massive industrial scale.
• Amino acid production: Immobilized aminoacylase is employed for the resolution of racemic mixtures of amino acids to produce L-amino acids.
• Biosensors: Immobilized enzymes like glucose oxidase are used in diagnostic devices to detect specific analytes in biological fluids.

Overall, immobilization enhances the thermal and pH stability of enzymes, allows for continuous processing in packed-bed reactors, and facilitates the termination of reactions by simple separation of the biocatalyst from the product stream.

A Biosensor is a compact analytical device that integrates a biological sensing element with a physicochemical transducer to detect, record, and transmit information regarding the presence or concentration of a specific analyte.

The main components are:

1. Bioreceptor (Sensing Element): A biological material such as enzymes, antibodies, nucleic acids, or whole cells that specifically recognizes and binds to the target analyte.
2. Transducer: The component that converts the biochemical reaction into a measurable physical signal, such as electrical, optical, or thermal energy.
3. Signal Processor: An electronic unit that amplifies, filters, and processes the raw signal from the transducer into a readable format.
4. Display/Output Unit: The interface that presents the processed data to the user, often as a digital reading or graphical representation.

Working Principle:

The process begins when the target analyte interacts specifically with the bioreceptor. This interaction triggers a biochemical change (e.g., change in pH, release of ions, or consumption of oxygen). The transducer detects this change and converts it into a proportional electrical signal. This signal is then amplified and processed by the electronics to provide a quantitative or semi-quantitative measurement of the analyte concentration.

Functions and Applications:

Biosensors are widely used in pharmaceutical and clinical settings for:

• Glucose Monitoring: The most common application, using glucose oxidase to measure blood sugar levels in diabetic patients.
• Drug Analysis: Detecting drug concentrations in biological fluids for therapeutic drug monitoring and pharmacokinetic studies.
• Pathogen Detection: Identifying bacteria, viruses, or toxins in clinical samples or during pharmaceutical manufacturing processes.
• Environmental Monitoring: Detecting pollutants or contaminants in water and soil samples.

The primary advantage of biosensors is their high specificity, rapid response time, and ability to perform real-time analysis in complex biological matrices.