Table 3 - Optimization of the citric acid production by Aspergillus niger through a metabolic flux balance model

Table 3. Discrimination among the occurrence of possible operative stages of the Krebs cycle, glycerol-P shuttle and alternatives routes for Ribulose-5 Phosphate generation [HMP vs TK+TA]. Model predictions in terms of specific respiratory rates are compared with the experimental observations.

ASSUMED PROCESSES

PREDICTED VALUES

Krebs
Cycle

HMP

TK +TA

Glycerol-P
Shuttle

fco₂^(a)(mmol. g^-1.h^-1)

Error
(%)

fo₂^(b)(mmol. g^-1.h^-1)

Error
(%)

Active

Active

Inactive

Present

1.08

(+3.8)

2.15

(- 0.5)

Inactive

Active

Inactive

Present

0.18

(- 83)

1.53

(- 29)

Active

Active

Inactive

Absent

1.08

(+3.8)

N.D^(c)

N.D^(c)

Active

Inactive

Active

Present

0.86

(- 17)

1.84

(- 15)

Active

Inactive

Active

Absent

1.08

(+3.8)

N.D^(c)

N.D^(c)

Inactive

Inactive

Active

Present

0

(-100)

1.86

(-13.8)

Carbon flux distribution estimations based on the proposed mechanisms. Carbon input (glucose) and carbon outputs (citric acid, arabitol, glycerol, mannitol, erythritol and biomass) being at fixed values.

Values determined as the half of the total available reduction equivalents at mitochondrial compartment from the flux above distribution.

N D: not determined.

Supported by UNESCO / MIRCEN network

Home | Mail to Editor | Search | Archive

ASSUMED PROCESSES				PREDICTED VALUES
Krebs Cycle	HMP	TK +TA	Glycerol-P Shuttle	fco₂^(a)(mmol. g^-1.h^-1)	Error (%)	fo₂^(b)(mmol. g^-1.h^-1)	Error (%)
Active	Active	Inactive	Present	1.08	(+3.8)	2.15	(- 0.5)
Inactive	Active	Inactive	Present	0.18	(- 83)	1.53	(- 29)
Active	Active	Inactive	Absent	1.08	(+3.8)	N.D^(c)	N.D^(c)
Active	Inactive	Active	Present	0.86	(- 17)	1.84	(- 15)
Active	Inactive	Active	Absent	1.08	(+3.8)	N.D^(c)	N.D^(c)
Inactive	Inactive	Active	Present	0	(-100)	1.86	(-13.8)