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Table 4 Growth parameters with glucose as carbon source

From: Simultaneously improving xylose fermentation and tolerance to lignocellulosic inhibitors through evolutionary engineering of recombinant Saccharomyces cerevisiaeharbouring xylose isomerase

Parameter

No liquor

Supplemented with liquor

 

D5A+

D5A+

D5A+H

TMB3400

MEL2

MH1000

μmax (h-1)

0.56 ± 0.01

0.03 ± 0.01

0.29 ± 0.02

0.22 ± 0.00

0.21 ± 0.01

0.23 ± 0.01

Biomass† (g/L)

1.42 ± 0.06

1.18 ± 0.05

2.13 ± 0.04

1.32 ± 0.02

1.46 ± 0.02

1.07 ± 0.02

Ethanol† (g/L)

7.77 ± 0.15

8.86 ± 0.30

7.76 ± 0.13

8.48 ± 0.14

8.28 ± 0.02

8.55 ± 0.50

Glycerol† (g/L)

0.67 ± 0.01

0.44 ± 0.00

0.51 ± 0.01

0.46 ± 0.01

0.39 ± 0.07

0.43 ± 0.06

Yx/s‡ (g/g)

0.08 ± 0.00

0.06 ± 0.01

0.1 ± 0.00

0.06 ± 0.01

0.08 ± 0.00

0.05 ± 0.00

Yp/s§ (g/g)

0.42 ± 0.01

0.43 ± 0.03

0.37 ± 0.01

0.42 ± 0.01

0.43 ± 0.00

0.44 ± 0.02

Yp/x¶ (g/g)

5.18 ± 0.03

5.37 ± 0.2

3.58 ± 0.2

6.16 ± 0.7

6.08 ± 0.06

6.85 ± 0.3

qs* (g/gh)

3.66 ± 0.07

1.6 ± 0.14

1.1 ± 0.1

3.03 ± 0.1

4.64 ± 0.38

6.4 ± 0.1

qp†† (g/gh)

2.25 ± 0.00

0.69 ± 0.00

0.41 ± 0.00

0.54 ± 0.03

0.85 ± 0.03

1.8 ± 0.02

  1. Yield coefficients and specific rates of growth, substrate consumption and ethanol production for strains D5A+, D5A+H, TMB3400, MH1000 and MEL2 with 20 g glucose/L as primary carbon source in batch culture with and without with 50% (v/v) hydrolysate liquor from steam-pretreated triticale. Standard deviations from duplicate fermentations are shown.
  2. †Biomass and product concentrations at the end of the exponential growth phase.
  3. ‡Yx/s, biomass yield on glucose, calculated from the slope of the biomass concentration plotted as a function of the residual glucose concentration.
  4. §Yp/s, ethanol yield on glucose, calculated from the slope of the ethanol concentration plotted as a function of the residual glucose concentration.
  5. ¶Yp/x, ethanol yield on biomass, calculated from the slope of the ethanol concentration plotted as a function of the biomass concentration.
  6. *qs, specific rate of substrate utilisation in g glucose/g biomass per hour during the mid-exponential phase.
  7. ††qp, specific rate of product formation in g ethanol/g biomass per hour during the mid-exponential phase.