#Question id: 14273
#SCPH05 I Biotechnology
Nicotiana tabacum cells are cultured to high density for
production of polysaccharide gum. The reactor used is a stirred tank,
containing initially 100 litres medium. The maximum specific growth rate of the
culture is 0.18 d-1 and the yield of biomass from substrate is 0.5 g
g-l. The concentration of growth-limiting substrate in the medium is
3% (w/v). The reactor is inoculated with 1.5 g l- 1 cells and
operated in batch until the substrate is virtually exhausted; medium flow is
then started at a rate of 4 l d-1. Fed-batch operation occurs under
quasi-steady-state conditions. Estimate the batch culture time. ____________________
#Question id: 14274
#SCPH05 I Biotechnology
Nicotiana tabacum cells are cultured to high density for
production of polysaccharide gum. The reactor used is a stirred tank,
containing initially 100 litres medium. The maximum specific growth rate of the
culture is 0.18 d-1 and the yield of biomass from substrate is 0.5 g
g-l. The concentration of growth-limiting substrate in the medium is
3% (w/v). The reactor is inoculated with 1.5 g l- 1 cells and
operated in batch until the substrate is virtually exhausted; medium flow is
then started at a rate of 4 l d-1. Fed-batch operation occurs under
quasi-steady-state conditions. Estimate final biomass concentration?
________________
#Question id: 14275
#SCPH05 I Biotechnology
Nicotiana tabacum cells are cultured
to high density for production of polysaccharide gum. The reactor used is a
stirred tank, containing initially 100 litres medium. The maximum specific
growth rate of the culture is 0.18 d-1 and the yield of biomass from
substrate is 0.5 g g-l. The concentration of growth-limiting
substrate in the medium is 3% (w/v). The reactor is inoculated with 1.5 g l-
1 cells and operated in batch until the substrate is virtually exhausted;
medium flow is then started at a rate of 4 l d-1. Fed-batch
operation occurs under quasi-steady-state conditions. Fed-batch operation
is carried out for 40 d. What is the final mass of cells in the reactor?
_____________________
#Question id: 14276
#SCPH05 I Biotechnology
Nicotiana tabacum cells are cultured to high density for production of polysaccharide gum. The reactor used is a stirred tank, containing initially 100 litres medium. The maximum specific growth rate of the culture is 0.18 d-1 and the yield of biomass from substrate is 0.5 g g-l. The concentration of growth-limiting substrate in the medium is 3% (w/v). The reactor is inoculated with 1.5 g l- 1 cells and operated in batch until the substrate is virtually exhausted; medium flow is then started at a rate of 4 l d-1. Fed-batch operation occurs under quasi-steady-state condition. The fermenter is available 275 d per year with a downtime between runs of 24 h. How much plant cell biomass is produced annually? ___________________
#Question id: 14277
#SCPH05 I Biotechnology
Lactobacillus casei is propagated under essentially
anaerobic conditions to provide a starter culture for manufacture of Swiss cheese.
The culture produces lactic acid as a by-product of energy metabolism. The
system has the following characteristics:
A stirred fermenter is operated in fed-batch mode at
quasisteady state with a feed flow rate of 4 m3 h-1 and
feed substrate concentration of 80 kg m-3. After 6 h, the liquid
volume is 40 m3. What mass of cells is produced after 6 h fed-batch
operation?
__________________
#Question id: 14278
#SCPH05 I Biotechnology
Stirrer has a power number (Np) 10. If the stirrer speed (N) is 1s^-1, its diameter D=1m and the density of the medium is 1000 kg/m^3, the ungassed power input (P) in watts is