Scaling up and scaling down the production of galactaric acid from pectin using Trichoderma reesei

Table 1 Galactaric acid production by T. reesei expressing udh under promoters pCBH1, pcDNA1, pPDC1 or pGPDA

Strain	pCBH1	pcDNA1	pPDC1	pGPDA ^a
24-well plates—d-galacturonate
Galactaric acid (g L⁻¹)	11.1 ± 0.2	9.4 ± 0.4	9.8 ± 0.1	8.8
Galactaric acid production rate (72–120 h) (g l⁻¹ h⁻¹)	0.13 ± 0.01	0.12 ± 0.00	0.12 ± 0.00	0.11
Yield galactaric/d-galacturonic (g g⁻¹)	0.95 ± 0.02	0.87 ± 0.02	0.89 ± 0.00	0.89
24-well plates—pectin
Galactaric acid (g L⁻¹)	11.6 ± 0.2	11.5 ± 0.3	11.4 ± 0.1	10.5
Galactaric acid production rate (72–120 h) (g L⁻¹ h⁻¹)	0.12 ± 0.04	0.11 ± 0.00	0.11 ± 0.00	0.13
Yield galactaric/d-galacturonic (g g⁻¹)	0.84 ± 0.03	0.90 ± 0.03	0.89 ± 0.03	0.76
0.5 L bioreactors—d-galacturonate
Galactaric acid (g L⁻¹)	15.7	13.6	16.0	19.7
Galactaric acid production rate (0–72 h) (g L⁻¹ h⁻¹)	0.22	0.21	0.09	0.19
Yield galactaric/d-galacturonic (g g⁻¹)	0.90	0.82	1.11	0.85
Maximum biomass (g L⁻¹)	9.5 ± 0.2	9.0 ± 0.3	6.5 ± 0.5	7.9 ± 0.3

Galactaric acid production (titre, rate of production and yield on d-galacturonic acid) in 24-well plates and in 0.5 L bioreactors using either d-galacturonic acid or pectin (Sigma) as substrate, with lactose as co-substrate. Maximum biomass in bioreactors was observed at 50 (pCBH1, pcDNA1, pGPDA) or 72 (pPDC1) h after which time biomass decreases (see also Fig. 3). Values are mean ± sem for three replicates
^aStrain VTT D-161646

ISSN: 1475-2859