L4: Centrifugation Flashcards
Which microorganisms produce most industrial enzymes?
Bacteria and fungi
What bulk enzyme is low priced and low molecular weight(MW)?
Succinic acid
What bulk enzymes are high priced and high molecular weight (MW)?
- Human growth hormone
- Monoclonal antibodies
What is the equation for the sigma factor?
Q=ug*∑
Q is the throughput (m3/s)
∑ has units of m2 and is equivalent to the cross sectional area of a settler with the same capacity
What is the equation for the sigma factor for bowl centrifuge?
∑=piω^2(R^2-rc^2)H/gln(R/r)
ω is the angular velocity (rad/s)
R is the outer radius of the bowl (m)
rc is the radius of the clarified discharge weir (m)
H is the height of the bowl (m)
r is the inner radius of the liquid in the bowl (m)
g is the acceleration due to gravity (m/s2)
What is the Disc Stack Centrifuge Capacity formula?
∑=(2/3)piω^2n(R^3-rc^3)/g*tanθ
ω is the angular velocity (rad/s)
n is the number of discs
R is the outer radius of the discs (m)
r is the inner radius of the discs (m)
θ is the angle between disc and vertical (rad). Radians = Degrees × π/180°
g is the acceleration due to gravity (m/s^2)
What are the main industries that use industrial enzymes, and what purposes do they serve?
Food (bread, dairy, fruit juice), textile (fabric treatment), detergent (low-temp washing), pulp/paper (bleaching), animal feed (absorption), and leather (dehairing).
What are the primary microorganisms used for enzyme production?
Aspergillus, Trichoderma, Bacillus, and Kluyveromyces.
What is the primary goal when producing industrial enzymes?
To optimize production costs, achieve high yields, and maintain enzyme stability.
What are the main stages in the enzyme production process?
Fermentation, downstream processing (DSP), and formulation.
Explain the difference between intracellular and extracellular enzyme production.
Intracellular requires cell disruption for enzyme recovery; extracellular is secreted but may require protection from proteases.
Why is extracellular enzyme production preferred
It avoids the need for cell disruption, simplifying recovery and reducing costs.
What is the typical size and volume of fermentation tanks used in industrial enzyme production?
Tanks of up to 100 m³ with an operating volume of 80 m³.
What are the primary techniques for separating cells after fermentation?
Centrifugation and filtration.
Describe the function of a disc stack centrifuge in enzyme production.
It separates cells from the liquid phase, isolating extracellular products with high clarity.
What is the purpose of the sigma factor in centrifugation?
It helps calculate the capacity of a centrifuge based on its geometric and operating parameters.
Why are high-throughput disc stack centrifuges preferred over microfiltration in some processes?
They handle larger volumes, are faster, and work well for separating cells from the liquid phase.
What is the role of ultrafiltration in the purification process?
It removes smaller proteins, sugars, and salts, concentrating the enzyme product.
List some of the primary costs in enzyme production.
Raw materials, equipment, labor, utilities, and product recovery.
What does the process scale in enzyme production depend on?
Market demand, typically estimated to produce around 500 tons per year.
What are the challenges of maintaining sterility in centrifugation?
The need to prevent contamination, manage cooling, and control residence time.
What factors affect particle settling during centrifugation?
Weight, drag of the fluid, buoyancy, and particle size (Stokes Law).
Describe the purpose of precipitation in enzyme recovery.
To separate insoluble proteins from soluble proteins through pH adjustment or the addition of salts.
What are the main goals in the formulation stage of enzyme production?
Achieving product stability, matching recovery yield, and ensuring product delivery specifications.
