Recovery and Purification of Bio-Products Strategies to recovery and purify bio-products Solid-liquid separation Cell disruption Separation of soluble products Finishing steps for purification

Recovery and Purification of Bio-Products Strategies to recovery and purify bio-products Unique characteristics of bioseparation products: - the products are in dilute concentration in an aqueous medium. e.g therapeutic protein 0.01mg/l. - The products are usually temperature sensitive. - There is a great variety of products to be separated. - The products can be intracellular, often as insoluble inclusion bodies. - The physical and chemical properties of products are similar to contaminants. - Extremely high purity and homogeneity may be needed for human care.

Recovery and Purification of Bio-Products Strategies to recovery and purify bio-products Fementer Solid-liquid separation Recovery Purification Supernatant Cells Cell products Cell rupture Cell debris Crystallization and drying

Recovery and Purification of Bio-Products Strategies to recovery and purify bio-products Fementer Solid-liquid separation Recovery Purification Supernatant Cells Cell products Cell rupture Cell debris Crystallization and drying

Recovery and Purification of Bio-Products Liquid and solid separation - solid particles: mainly cellular mass, specific gravity 1.05-1.1. size (diameter): bacterial cells: 0.5-3 µm yeast cells: 5 -10 µm mold: 5-15 µm in diameter and 50-500 µm in length animal cells: 10 µm plant cells: 20 µm

Recovery and Purification of Bio-Products Liquid and solid separation Solid particles: mainly cellular mass Methods: filtration and centrifuge

Liquid-Solid Separation Filtration Physical separation of solid particles from liquid or gas. a porous medium: allow fluid to pass through solid particles to be retained. Slurry flow Filtrate Filter medium Filter cake

Liquid-Solid Separation Filtration Rotary vacuum filtration Particle size: greater than 10 µm, yeast, mold, animal or plant cells. i.e. mycelium separation for antibiotics production or waste water treatment Microfiltration Particle size: 0.1 - 10 µm, bacterial and yeast cells. Ultrafiltration Size: 10-200 Å, Cell debris, macromolecules

Rotary Vacuum Filter A rotary vacuum filter is a continuous filter partially submerged in the slurry. - A drum is covered with a filter medium. Vacuum is applied to within the drum As the drum rotates, The solid constituent is separated by retained on the porous medium The liquid is drawn through the cake into the inner filtrate pipes. Each revolution consists of cake formation, cake washing (if required), drying and cake discharge.

http://www.rpi.edu/dept/chem-eng/Biotech-Environ/Canada/rotvac.htm http://www.solidliquid-separation.com/ VacuumFilters/vacuum.htm http://www.komline.com/Products_Services/ Filtration/RotaryVac.html

Rotary Vacuum Filter The rate of filtration (the flow of the filtrate) for a constant pressure (vaccum) filtration operation can be determined by

Rotary Vacuum Filter

Rotary Vacuum Filter Assuming incompressible cake: constant α, & constant pressure, and integrating the previous equation (V at t, V=0 at t=0) yields t/V V

Rotary Vacuum Filter To design a scaled-up rotary vaccum filter If given a total volume of fermentation broth Vb and required time tb to complete the filtration task at the large scale, determine the filter surface area. Based on the results from the smaller filter (incompressible cake: same α, medium & pressure drop):

Rotary Vacuum Filter Relating the design equation to the rotation speed In a rotating drum filter, The drum rotates at a constant speed (n rps) Only a fraction of drum-surface area is immersed in suspension reservoir (φ) Ruth equation can be rewritten as

Liquid-Solid Separation Filtration Rotary vacuum filtration Particle size: greater than 10 µm, yeast, mold, animal or plant cells. i.e. mycelium separation for antibiotics production or waste water treatment Microfiltration Particle size: 0.1 - 10 µm, bacterial and yeast cells. Ultrafiltration Size: 10-200 Å, Cell debris, macromolecules

Liquid-Solid Separation Filtration Microfiltration Particle size: 0.1 - 10 µm, bacterial and yeast cells. Ultrafiltration Size: 10-200 Å, Cell debris, macromolecules (antibiotics, proteins, polysaccharides) Use membrane as porous medium for filtration. Challenge: gel formation on the surface of membrane. Solution: cross-flow (tangential flow filtration) Pressure P1 Pressure P2 Feed in Feed out

Liquid-Solid Separation Filtration Centrifuge - Particle size: 100-0.1 µm - more expensive than filtration - limited for scale-up - drive force: centrifugal force