Bio301 MSE2008
Student name……………………………………………………
Student number ……………………………………………….
@1 kLa
1Fs) The kLa value…
increases with oxygen concentration
decreases with oxygen concentration
is independent of the oxygen concentration
increases with increasing oxygen partial pressure
decreases with increasing oxygen partial pressure
is independent of the oxygen partial pressure
@2 OUR
1Fs) A microbial culture had an oxygen uptake rate of 100 mg/L/h in a chemostat of a
steady state dissolved oxygen concentration of 4 mg/L. When the dilution rate was
increased the dissolved oxygen concentration dropped to 2 mg/L. What is the new
oxygen uptake rate when the saturation concentration is 8 mg/L. Select the closest
value
125
200
150
75
50
175
144
80
@3 Chemostat
1Fs) What is the microbial specific growth rate in h-1 of in a 8 L chemostat operated
under steady state conditions with a medium inflow rate of 40 mL per minute?
0.1
0.2
0.3
0.4
0.5
0.6
0.8
0.15
@ 4 Oxygen transfer
1Fs) A bioreactor with a kLa value of 40 h-1 was aerated with air. As expected the
oxygen concentration saturation concentration was 8 mg/L. The oxygen steady state of
the microbial culture was 3 mg/L. What would be the new dissolved oxygen
concentration if instead of air, pure oxygen was used?
0.1
0.2
0.3
0.4
0.5
0.6
0.8
0.15
@5 Stoichiometry
1Fs) How many moles of oxygen are needed for the complete oxidation of 1 mol of
isopropanol (CH3-CHOH-CH3)
@6 Stoichiometry
1Fs) How many moles of NADH can be generated from the oxidation of 1 mole of
pyruvic acid (CH3-CO-COOH)
@7 Stoichiometry
1Fs) How many moles of sulfite (SO3--) need to be reduced to H2S for the oxidation of
1 mole of glucose ( (CH2O)6 )
@8 Stoichiometry
1Fs) In a rich medium containing the building blocks for biomass synthesis, how
much growth (in g of dry biomass/ L) would you expect from an aerobic microbial
culture that degrades acetaldehyde (CH3-COH) to CO2 ?
@9 Stoichiometry
1Fs) How many moles of ATP would you expect to be generated from the partial
aerobic oxidation of of glucose ( (CH2O)6 ) to 2 acetate (CH3-COOH) and 2 CO2?
@10 Stoichiometry
1Fs) How much oxygen is needed for the oxidation of ammonia (NH3) to nitrite (NO2)
@ 11 Growth
Considering the typical level of substrate concentration in a chemostat, a bacterium
with a lower kS value has
a disadvantage as it disables the effective consumption of the low substrate present
a disadvantage as it disables the effective consumption of the high substrate present
no advantage or disadvantage as the substrate concentration is high
an advantage as it enables effective consumption of the low substrate present
an advantage as it enables effective consumption of the high substrate present
no advantage or disadvantage as the substrate concentration is limiting
@ 12 Growth
Reduced electron carriers (NADH) are
a an advantage to all cells as they represent the key energy source
a problem to all cells as it prevents the reduction of electron acceptors
an advantage only to cells with an active electron transport chain, allowing the
generation of ATP
a problem to most cells as they require the input of ATP
an advantage to all cells as they can directly convert NADH to ATP via substrate
level phosphorylation
@ 13 Growth
At a substrate concentration of zero
the growth rate of bacteria will be zero as no energy can be generated
the growth rate will be negative as the bacteria need to carry our a maintenance
metabolism
bacteria can continue to grow as long as oxygen is available allowing respiration
bacteria go dormant and grow at the critical growth grate
bacteria keep multiplying but form smaller cells
the cell number will not increase, however individual cells can grow larger