Quiz Block 1

Question 1

Give an example of a filter aid normally used in industry

Answer 1

Diatomaceous earth or perlite

Question 2

In protein purification, what is the “salting out” process used for?

Answer 2

To precipitate the protein. The salt is added to decrease the solubility of protein submerged in liquid

Question 3

What are the three different downstream steps in which unit operations are divided into?

Answer 3

Separation of biomass
Concentration of product
Purification
(for enzymes & proteins a formulation step is added)

Question 4

What is chromatography used for?

Answer 4

Product purification and is normally used for expensive products

Question 5

Which extra steps require the recovery of intracellular product as compared to extracellular in DSP?

Answer 5

Disruption of membrane
Extraction
Removal of cells and debris

Question 6

The yield of product obtained by fermentation usually increases/decreases with increasing number of DP steps and increases/decreases as purity decreases

Answer 6

decreases - increases

Question 7

Mention two enzymes of industrial interest and their application

Answer 7

Amylase - used for bread production
Pectinase - used for juice

Question 8

In context of Process Design, Process Analysis usually comes before/after Process Synthesis?

Answer 8

after

Question 9

True or False: During process design, it is usually recommended to make the most difficult separations first, sp the easiest- and more expensive purification steps come later

Answer 9

FALSE - Easier, Less expensive steps should come first to remove larger particle impurities

Question 10

Name one (or more) disadvantage of centrifugation compared to filtration for removal of cells

Answer 10

Sterile operation is harder to use
Centrifugation is more energy intensive
Less safe on large-scale

Question 11

What is the driving force in a liquid-liquid extraction process and distillation?

Answer 11

For LLE: Affinity for solute
For Distillation: Boiling points

Question 12

How is the angular velocity of a rotor calculated to obtain units (s^(-1))?

Answer 12

angular velocity = omega * (2*pi/60)

Question 13

Explain why distillation becomes expensive when water is present in the solution?

Answer 13

Water binds well and has a higher boiling point. Distillation becomes more energy intensive, making it more expensive

Question 14

State the main advantage of using enzymes in detergent industry?

Answer 14

It is possible to clean clothes efficiently at a decreased temperature

Question 15

What kind of chemical is an antibody?

Answer 15

An antibody is a protein

Question 16

Write the equation used for the design of a centrfuge with units

Answer 16

Q [m^3/s]= Sigma [m^2] * Ug [m/s]
Flow rate/ Flux volumetric flow = Geometry of centrifuge * Characteristic velocity of solute

Question 17

Name one microorganism commonly used to produce enzymes industrially

Answer 17

E.Coli
Asperigillus
Bacillus

Question 18

What does the formulation step consist of during production of enzymes?

Answer 18

The formulation step for the stabilization of the product

Question 19

UltraFiltration/DiaFiltration can be used for purification of lipids/proteins while ReverseOsmosis/Ultrafiltration can be used for removal of minerals/acids in a stream

Answer 19

Ultrafiltration - proteins
Reverse Osmosis - minerals and salts

Question 20

Cross-flow/dead-end is the industrial operation mode usually preferred for membrane filtration, because x

Answer 20

Cross flow operation mode - because fouling is decreased. The pharmaceutical industry uses dead-end

Question 21

Name the two typical unit operations that are used for biomass removal

Answer 21

Filtration
Centrifugation

Question 22

True or False: Rotary vacuum filters may operate continuously for long periods of time

Answer 22

True

Question 23

The feed stream of a centrifuge is (100 m^3/h) contains 10% cells. Calculate yield of supernatant if 45 m^3/h of liquid is present in the pellet (no cells in supernatant).

Answer 23

Feed = 100m^3/h and cells = 0.1100=10m^3/h so liquid = 90m^3/h. In supernatant liquid = 45 m^3/h since In pellet liquid = 45 m^3/h. Knowing yield = liquid in SUPERNATANT/ liquid in FEED meaning that yield = (45 m^3/h) / (90 m^3/h) = 0.5100 = 50%

Question 24

In which units do you normally express the productivity of a certain product in a fermenter?

Answer 24

g/L*h (concentration (g/L) per time unit (h))

Question 25

In the solution-diffusion equation, the flux of solvent is directly/inversely proportional to the osmotic pressure, and directly/inversely proportional to the applied pressure

Answer 25

Inversely proportional to osmotic pressure

Directly proportional to applied pressure

Question 26

Divide related terms into two groups:
Centrifugation - Filter Aid - Stokes equation - Tubular bowl - Filtration - Angular velocity

Answer 26

Filtration, Filter Aid

Centrifugation, Tubular bowl, Stokes Equation, Angular velocity

Question 27

Name the two types of membrane modules which are most used in industry and explain

Answer 27

Spiral
Hollow fibre: Possible to compress a large volume of membranes

Question 28

What is concentration polarisation in the context of membrane technology?

Answer 28

Concentration gradient in feed solution

Question 29

True or False: In Process Design, it is always preferable to use consecutive unit operations that use different driving forces.

Answer 29

True

Question 30

In order to solubilize a protein, one should work far/near its isoelectric point

Answer 30

Far