Energy consuming and energy producing
products
Technology for Biobased Products
Sef Heijnen, Department of Biotechnology, Faculty of Applied Sciences
Pseudo steady state flux coupling
Substrate limitation qs(cs) (constant T, pH, pressure)
qp(cs)
µ(cs)
Black
qs(cs)
box qCO2(cs)
qi(cs)
Product consumes energy = aerobic
Product produces energy = anaerobic
Substrate uptake
Energy consuming and energy producing product
cs
Hyperbolic func on of qs
qs = qs,max *
K + cs
s
Parameters qs,max and Ks
" Assumed to be constant
cs
" Need to be determined
" Depends on organism,
substrate, T and pH
s
q
Substrate for maintenance energy
Degradation
Repair
energy
Leakage ms
Energy consuming product Energy producing product
Aerobic Anaerobic
ms = 0.005 (mol glucose/h)/mol x ms = 0.05 (mol glucose/h)/mol x
Black box model energy consuming
product µ(cs)
Branchpoint
|a| mol s
mol x
|b| mol s
mol p
qs(cs) qp(cs)
|ms|
product maintenance
growth
qs = a*µ + b*qp + ms
Herbert-Pirt substrate distribution relation
Kinetic coupling of qp and µ
qp(µ) = non-linear
Aerobic black box PDO model
Glucose uptake rate -qs = 0.20 cs / (0.5 + cs)
product maintenance
growth
Herbert-Pirt substrate distribution -qs = 0.25 µ + 0.8 qp+ 0.005
Non-linear qp(µ) relation qp = 0.05 µ /(0.03 + µ)
3 equations
= 1 free variable which can be µ or cs
4 variables
Economics aerobic PDO production
qs
mol glucose
= = 0.25 µ + 0.8 qp+ 0.005
mol PDO qp
0.05 µ /(0.03 + µ)
0.25 µ + 0.8 + 0.005 .
|qs/qp|=
0.05 µ /(0.03 + µ) 0.05 µ /(0.03 + µ)
|qs/qp|= mol glucose = 1.05 + 5µ + 0.005/µ
mol PDO
Economics aerobic PDO production
-qs,opt = 0.25 µ,opt + 0.8 qp,opt + 0.005
µopt = 0.0245
-qs,opt = 0.25*0.0245 + 0.8*0.0227 + 0.005
qp,opt= 0.0227
qs,opt = 0.0294
-qs,opt = 0.0062 + 0.0182 + 0.005
growth = 21% product = 62% maintenance = 17%
Anaerobic BB model energy producing
product µ(cs)
|a|
energy
qs(cs)
ethanol
|ms|
qp(cs)
growth maintenance
qs = a*µ + ms
Herbert-Pirt substrate distribution relation
Stoichiometric (energy) coupling of qp and µ
qp = ap*µ + mp = linear
Summary black box model
Energy consuming product Energy producing product
Aerobic Anaerobic
cs
cs
qs = qs,max *
qs = qs,max *
K + cs
K + cs
s
s
qs = a*µ + b* qp + ms
qs = a*µ + ms
qp (µ) is non linear qp = ap*µ + mp which is linear
Kinetic coupling qp and µ
Stoichiometric (energy) coupling
qp and µ
See you in the next unit!