Aerobic PDO process: improving
sustainability
Sef Heijnen, Department of Biotechnology, Faculty of Applied Sciences
FN,out = 3760969 (mol/h)
yO2,out = 0.0725
The process scheme
yCO2,out = 0.1614
Fm,in (kg/h) = 71225 kg/h
yw,out = 0.0600
ptop = 1 bar
Broth mass =
Gas transfer:
2250 tonne
O2 = 433207 mol O2/h
Heat = 51434 kJ/s
NH3 = 35970 mol NH3/h
Rp= 165 000 mol
H2O = 225658 mol H2O/h
PDO/h
CO2 = 607200 mol CO2/h
FN,in = 3361320 (mol/h)
yO2,in = 0.2100
35°C
yw,in = 0
Fm,out (kg/h) = 54920 kg/h
yCO2,in= 0
FN,NH3 = 35970 (mol/h)
More sustainable:  pushing the limits
Less consump on/produc on per mol PDO of everything
Lower coefficients in the process reac on (lower variable cost)
Lower DSP cost: Higher PDO concentra on in broth
Glucose in feed at solubility limit
Lower capital cost: Smaller fermenters
High O2 transport rate in the fermenter: week 4
Low O2/PDO ra o in process reac on
Lower qi/qp ra os: Dissect the process reac on
qNH
+ qO qCO qH O qH + qQ
qs µ +
+
42 2 2
*C6 H12O6 + * NH4 + *O2 + *C1H1.8O0.5N0.2 +1*C3H8O2 + *CO2 + * H2O + *H + (heat)
qp qp qp qp qp qp
qp qp
ź/qp Biomass reac on
+
Minimize coefficients
(+1) · PDO reac on
by increasing qp
+
( ms/qp) · Glucose catabolism
Lowering qi/qp ra os: the kine c approach by
increasing qp by metabolic engineering
Wild type Mutant
qp,max
0.05 0.10
(=Ä…)
0.04
źopt 0.025 0.014
Metabolic
0.03
engineering
qp,opt 0.023 0.059
qs/ qp 1.295 0.95 0.02
ź / qp 1.09 0.24
0.01
qO2 / qp 2.63 1.42
0
cs,opt 85 10 6 192 10 6
0 0.005 0.010 0.015 0.02 0.025 0.03 0.035
µ (h-1)
p
q
Lowering qi/qp ra os: the stoichiometric approach
of metabolic engineering
PDO reac on of the Black Box model:
0.80 C6H12O6 0.80 O2 + 1.00 C3H8O2 + 1.80 CO2 + H2O
Catabolic part:
0.80/6 C6H12O6 0.80 O2 + 0.80/6 CO2 + 0.8/6H2O
Anabolic part,  substract catabolic part from PDO reac on :
0.666 C6H12O6 0 O2 + 1.00 C3H8O2 + 1 CO2 + 0 H2O
Limit of stoichiometric approach of metabolic
engineering: Anaerobic holy grail
Stoichiometric approach: decrease O2 stoichiometry
0.80 mol O2 /mol PDO
0?
" Improved ATP produc on / O2
" Less ATP consump on / mol PDO
" & ?
Theore cal PDO reac on
0.6666 C6H12O6  0 O2 + 1 C3H8O2 + 1CO2 + 110 kJ Gibbs energy
Lower DSP cost: focus on less water
High PDO concentra on
More concentrated glucose solu on: operate at glucose solubility limit
water free feedstock
" Ethanol
From sustainable
" Methanol
feedstocks
" H2/CO syngas
High fermenta on temperature to increase water evapora on
See you in the next unit!