1. “Solid state fermentation of sweet sorghum by Saccharomyces cerevisiae to bioethanol production”
Karamousantas, D., Th. Varzakas (Technological Educational Institution of Kalamata – Hellas),
D. Arapoglou, C. Israilides (Institute of Technology of Agricultural Products – Hellas)

4. BioFuel - Bioethanol
Ethanol is attractive out of the many alternative energy sources because it can be widely used as an all around motor fuel.

6. Why Bioethanol?
Politico-economic impact.
Surplus value of raw material
Increase of places of work and rural income
Holding of rural population
B. Environmental impact
Renewable raw material (Biomass)
Decrease of environmental pollution
Reducing energy dependence

8. National target for Greece according the new E.U. Directive
Share of energy from renewable sources in final consumption of energy (2005)
Share Renewables in the final energy demand by 2020
6,9%
18%

10. Sweet Sorghum Sugar content 9.6 -20.3 per cent of raw whole stalks
High content of soluble sugar and cellulose

13. S. cerevisiae
Juice extraction
Acidic Hydrolysis
Whole stalks
Sweet Sorghum Stalks
Ethanol Production

14. Varieties Moisture % Extracted Juice (% v/w) Total Sugar of Juice %
Moisture, extracted juice as per cent of whole fresh material and total sugar of juice, of 8 tested sweet sorghum varieties.
Varieties
Moisture %
Extracted Juice
(% v/w)
Total Sugar
of Juice %
(g/v)
No 1
86.32
45.85
11.35
No 2
69.20
46.60
12.54
No 3
88.08
55.33
12.96
No 4
69.90
52.63
14.70
No 5
74.26
55.36
8.89
No 6
69.95
47.15
13.56
No 7
70.66
42.64
8.93
H133
63.76
38.72
16.39

15. % of max theoretical yield
Fermentation parameters of sweet sorghum juice with S. Cerevisiae var. Bayanus for ethanol production.
Varieties
Total Sugar Initial
gL-1
Total Sugar Final
Total Sugar
Consumption
(TSC)
Ethanol ProducedgL-1
Ethanol Yield
g EtOH /
g TSC
% of max theoretical yield
No 1
18.923
1.084
17.839
5.295
0.297
59.36
No 2
20.893
1.690
19.203
8.143
0.424
84.81
No 3
21.596
1.707
19.889
7.288
0.366
73.29
No 4
24.500
1.601
22.899
8.739
0.382
76.33
No 5
14.821
0.850
13.971
5.627
0.403
80.55
No 6
22.604
2.246
20.358
7.180
0.353
70.54
No 7
14.881
1.276
13.605
4.611
0.339
67.79
H133
27.316
2.642
24.674
9.566
0.388
77.54

16. % of max theoretical yield
Fermentation parameters of sweet sorghum stalk with S. Cerevisiae var. Bayanus for ethanol production.
Varieties
Total Sugar Entered
gL-1
Total Sugar Final
Total Sugar
Consumption
(TSC) gL-1
Ethanol gL-1
Ethanol Yield
g EtOH /
g TSC
% of max theoretical yield
No 1
28.267
1.388
26.879
8.925
0.332
66.41
No 2
30.973
1.850
29.124
12.215
0.419
83.88
No 3
24.236
1.476
22.760
10.632
0.467
93.43
No 4
30.932
1.701
29.230
13.109
0.448
89.69
No 5
26.432
1.928
24.504
9.405
0.384
76.76
No 6
30.273
2.051
28.222
10.770
0.382
76.32
No 7
29.894
1.364
28.530
8.565
0.300
60.04
H133
33.647
2.513
31.134
14.349
0.461
92.18

17. CONCLUSIONS
The fermentation of extracted juice and hydrolyzed stalk from eight sweet sorghum varieties by Saccharomyces cerevisae var. bayanus for ethanol production was studied.
There was great variation in ethanol production among different varieties.
Ethanol production was in high levels in most of varieties.
Whole stalks produced more ethanol than juice.