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Table 3 Fermentation results for fresh sweet potato and flour at different dry matter to water ratios

From: Evaluation of sweet potato for fuel bioethanol production: hydrolysis and fermentation

Sweet potato

Dry matter to water ratio (w/v)

Ethanol (g/L)

Glycerol (g/L)

Sugar conversion (%) (*)

Efficiency (%) ()

Productivity (g/Lh)

Industrial yield (L ethanol/t sweet potato dry base) ()

Agroindustrial yield (L ethanol/ha) (#,†)

Fresh

1:2.2 ()

100 ± 11

9 ± 1

67 ± 7

92 ± 1

2.1 ± 0.3

320 ± 37

3170 ± 360

 

1:5

63 ± 6

8 ± 1

88 ± 3

82 ± 4

2.6 ± 0.3

380 ± 34

3730 ± 330

 

1:8

45 ± 5

8 ± 1

100 ± 0

84 ± 9

3.2 ± 0.4

490 ± 54

4790 ± 530

Flour

1:2

99 ± 1

12 ± 1

77 ± 2

79 ± 6

2.1 ± 0.1

305 ± 12

2990 ± 120

1:3

97 ± 5

9 ± 1

100 ± 0

92 ± 5

2.7 ± 0.2

460 ± 22

4490 ± 220

1:5

58 ± 1

7 ± 1

99 ± 2

90 ± 1

3.6 ± 0.2

425 ± 5

4170 ± 50

 

1:8

38 ± 4

4 ± 1

99 ± 0

84 ± 8

2.5 ± 0.2

410 ± 41

4020 ± 400

  1. (*) Sugar conversion based on the total sugar present in the raw material (fresh or flour).
  2. () Efficiency based on 0.511 g ethanol/g sugars as glucose.
  3. () Calculated using the ethanol density at 20°C (0.7894 kg/L).
  4. (#) Calculated based on an agriculture yield of 10 t/ha (dry matter) (Vilaró et al. 2009) and a distillation efficiency of 98%.
  5. () Fresh sweet potato without addition of water.