Downstream processing -Introduction and Process

Downstream processing

1. DownStream Processing Dr Sumitha J Associate Professor JBAS College for Women,Chennai-18

2. DSP Downstream processing (DSP) is a crucial part of biopharmaceutical and biochemical industries, responsible for isolating, purifying, and concentrating target products from complex biological mixtures. Recovery and purification of biomolecules (proteins, enzymes, antibodies etc.) from fermentation broths, tissue culture supernatants, or other biological matrices. Significance of DSP: Enables isolation of high-purity products for therapeutic, diagnostic, or industrial applications. Optimizes yield and cost-effectiveness of bioproduction processes. Contributes to product stability and shelf life.

3. Downstream Process Steps Cell harvesting: Separation of biomolecules from the host cells (centrifugation, filtration). Cell disruption: Releases intracellular products (enzymes, cell lysates) from the cells (chemical, mechanical, enzymatic methods). Clarification: Removal of cell debris and insoluble material (centrifugation, filtration). Pre-purification: Initial concentration and partial purification of the target product (salting out, precipitation). Chromatography: Main isolation and purification step (affity chromatography, ion exchange chromatography, size exclusion chromatography etc.). Polishing: Final purification to remove trace contaminants (membrane filtration, polishing chromatography). Concentration and formulation: Concentrates the final product to desired volume and adds stabilizing agents for storage and use.

4. Filtration

5. Mechanism: Uses a physical barrier (membrane or filter bed) to allow passage of some components while retaining others based on size, shape, and surface properties. Applications: Clarification: Removes smaller cell debris and particles not settled by centrifugation. Pre-purification: Concentrates target molecules using membranes with specific pore sizes or surface functionalities. Polishing: Sterilizes final product by removing bacteria and viruses using specially designed filters. Types of filters: Depth filters (e.g., diatomaceous earth) for removing large particles, membrane filters (e.g., ultrafiltration, sterile) for selective separation based on size or charge.

6. techniques of filtration Surface filtration Depth filtration Centrifugal filtration Rotating drum vacuum filtration

7. Surface Filtration Surface filtration plays a crucial role in various industrial processes by separating solids from liquids or gases using a porous medium. Unlike depth filters, which capture particles within their structure, surface filters allow the fluid to pass through while retaining larger particles on the surface. Here's a deeper dive into their principles, diagrams, and applications: Principles: Size exclusion: Particles larger than the pores of the filter medium are physically blocked, forming a cake layer on the surface. Depth: In some cases, smaller particles may initially penetrate the surface layer but get trapped within the cake itself due to adhesion or entrapment. Adhesion: Certain filter media utilize specific surface properties to attract and capture particles based on their chemical or physical characteristics.

8. Types Membrane Surface Filters Screen Surface Filters

9. Surface Filtration - Applications Surface filtration finds use across diverse industries, Beverage industry: Clarifying juices, beers, and wines by removing yeast, bacteria, and other solid particles. Chemical industry: Separating catalysts, precipitates, and unreacted materials from reaction mixtures. Water treatment: Removing sand, silt, and algae from raw water for purification. Air filtration: Filtering dust, pollen, and other airborne particles from ventilation systems. Oil and gas production: Separating water and impurities from produced oil or gas.

10. Advantages: High efficiency and selectivity: Can specifically target desired particle sizes or types. Scalability: Available in various sizes and designs for different flow rates and capacities. Reusable: Some filters can be cleaned and reused multiple times, reducing costs.Ease of operation: Often simple to install and operate, requiring minimal maintenance. Disadvantages: Caking: Accumulation of particles on the surface can reduce flow rate and require frequent cleaning or filter replacement. Sensitivity to pressure: High pressure differentials can damage delicate filter media.Not suitable for fine particles: Smaller particles than the pore size may pass through, requiring additional filtration steps.

11. Depth Filtration Depth filtration offers a powerful tool for industrial separations by capturing particles throughout the depth of a porous medium, unlike surface filters that simply retain them on the surface. Let's delve into the principles, diagrams, and applications of this vital filtration technique: Principles: Tortuous path: The fluid takes a convoluted path through the dense structure of the filter medium, increasing the chances of particles colliding and getting trapped within the fibers or granules. Size exclusion: Large particles are physically blocked by the smaller pore spaces, while smaller ones may initially penetrate further but get hindered by subsequent layers. Adhesion and adsorption: Certain filter media utilize specific surface properties to attract and capture particles based on their chemical or physical characteristics.

12. Types Cartridge depth Filters Sheets and Pads depth Filter

13. Depth Filtration - Applications Depth filtration finds use across numerous industrial sectors, Chemical industry: Clarifying reaction mixtures, removing precipitates, and filtering catalyst particles. Food and beverage industry: Removing pulp and seeds from juices, filtering wines and beers, and clarifying syrups. Pharmaceutical industry: Separating cell debris and viruses from fermentation broths, clarifying protein solutions. Water treatment: Removing fine suspended solids and colloids from water for purification. Paints and coatings: Filtering out impurities and agglomerates for smooth, high-quality paint and coating finishes.

14. Advantages: High dirt-holding capacity: Can capture a large amount of particles before needing replacement. Effective for diverse particle sizes: Handles a wider range of particle sizes compared to surface filters. Gentle on sensitive materials: Less likely to damage fragile particles compared to high-pressure surface filtration. Relatively low cost: Often more affordable than some other filtration methods. Disadvantages: Clogging: Accumulation of particles within the filter can significantly reduce flow rate and require frequent replacement. Non-specific separation: Cannot always selectively target specific particle types. Disposal costs: Spent filters may require special disposal depending on the captured materials.

15. centrifugal filtration Industrial centrifugal filtration combines the power of centrifugation with the selectivity of filtration, offering a highly efficient separation technique for diverse industries. Let's explore its principles, visualize its operation, and discover its wide range of applications: Principles: Centrifugal Separation: A high-speed spinning rotor creates a strong centrifugal force that pushes heavier particles (e.g., solids) outwards towards the centrifuge wall, while lighter components (e.g., liquids) remain suspended. Filtration: A porous filter medium (e.g., membrane, screen) positioned at the centrifuge wall allows the liquid phase to pass through, while solids are retained and accumulate on the inner surface.

16. The feed mixture enters the rotor and is accelerated to high speeds. Feed Inlet: The mixture enters the rotor through a central feed tube. Flow Channels: The mixture flows radially outwards through channels within the rotor. Filter Layer: A porous filter medium lines the inner wall of the rotor, allowing liquid to pass through while retaining solids. Solid Cake: As solids accumulate on the filter, a cake layer forms on the filter medium. Liquid Effluent: The clarified liquid passes through the filter and exits the rotor through an outlet port.

17. Applications Industrial centrifugal filtration finds use in various sectors Chemical Industry: Separating catalysts, precipitates, and unreacted solids from reaction mixtures. Food and Beverage Industry: Clarifying juices, beers, and wines by removing yeast, bacteria, and other solid particles. Pharmaceutical Industry: Isolating and purifying proteins, enzymes, and other biomolecules from fermentation broths. Wastewater Treatment: Removing suspended solids and oil from wastewater for effective treatment. Metalworking Industry: Separating cutting fluids and metal chips during machining processes.

18. Advantages: High efficiency and capacity: Can handle large volumes and achieve high clarification levels in a single step. Precise separation: Selectively removes target particles based on their size and density. Continuous operation: Some designs allow for continuous feed and discharge, improving process efficiency. Gentle on sensitive materials: Minimizes shear stress on delicate biological particles compared to other filtration methods. Disadvantages: High initial investment: Centrifuges can be expensive compared to simple filtration equipment. Maintenance requirements: High-speed rotors require regular maintenance and balancing. Limited particle size range: Not suitable for separating very small particles (< 1 µm) effectively.

19. rotating drum vacuum filtration Industrial rotating drum vacuum filtration is a workhorse in solid-liquid separation, offering continuous and efficient processing in various industries. Principles: Rotating Drum: A cylindrical drum partially submerged in a tank of slurry rotates continuously. Vacuum Chamber: The internal drum space is maintained under a vacuum, creating a pressure difference across the filter medium. Filter Medium: A pre-coated or attached filter cloth covers the drum surface, allowing filtrate to pass through while retaining solids. Feed Slurry: The slurry continuously enters the tank and bathes the rotating drum. Cake Formation: Under the vacuum pressure, liquid is sucked through the filter medium, leaving a layer of solids (cake) on the drum surface. Cake Removal: As the drum rotates, it emerges from the slurry, and the cake is scraped or washed off by various mechanisms depending on the specific design. Filtrate Collection: The filtrate collected inside the drum passes through channels and exits the vacuum chamber.

20. A cylindrical drum partially submerged in a tank of slurry. The drum is divided into two chambers: Submerged chamber: This section is bathed in the slurry. The filter medium on the drum surface allows the liquid to pass through under vacuum pressure, forming a cake on top. Emerging chamber: As the drum rotates, this section emerges from the slurry, and the cake is removed by scraper blades or other mechanisms. The filtrate collected within the drum is then discharged.

21. Applications Chemical Industry: Recovering precipitated crystals, dewatering wet catalysts, and clarifying reaction mixtures. Mining and Mineral Processing: Dewatering mineral slurries, concentrating valuable minerals, and purifying mineral salts. Food and Beverage Industry: Clarifying juices, dewatering food products like starch and yeast, and recovering valuable byproducts. Wastewater Treatment: Removing sludge and solids from wastewater treatment processes. Pharmaceutical Industry: Dewatering fermentation broths, recovering valuable biomolecules, and clarifying pharmaceutical solutions.

22. Advantages: Continuous operation: Offers high throughput and efficiency compared to batch filtration methods. Scalability: Available in various sizes to handle small-scale pilot plants to large-scale industrial production. Versatile applications: Suitable for separating diverse solids from various liquid mixtures. Controlled cake thickness: Adjustable vacuum levels and scraper mechanisms allow precise control over cake thickness. Ease of automation: Can be readily integrated with automated process control systems for consistent operation. Disadvantages: High initial investment: Compared to simpler filtration methods, the equipment can be expensive. Maintenance requirements: Rotating parts and vacuum systems require regular maintenance and potential downtime. Not suitable for fine particles: May not be effective for separating very small particles due to potential blinding of the filter media.

23. Centrifugation