Table 3. Ethanol yield [Yp/s et (g/g)], xylitol yield [Yp/s xy (g/g)], ethanol productivity [Qp (g/L•h)], fermentation efficiency [η (%)], sugar (D-xylose and glucose) consumption (%), cell concentration (g/L), ethanol concentration (g/L) and xylitol concentration (g/L) in sugarcane bagasse hemicellulosic hydrolysate assays.
Yeast species | Yeast strains | Sugars consumption (%)1 | Cells (g/L) | Yp/s et (g/g)2 | Qp (g/L•h)3 | Η (%)4 | Ethanol concentration (g/L) | Yp/s xy (g/g)5 | Xylitol concentration (g/L) | Fermentation time (h)6 |
Candida lignosa | CBS 4705 | 55.3 | 7.8 | 0.16 | 0.05 | 31.6 | 4.6 | – | – | 96 |
Scheffersomyces stipitis | NRRL Y-7124 | 34.9 | 3.4 | 0.25 | 0.10 | 49.3 | 4.9 | – | – | 48 |
S. stipitis | UFMG-XMD-15.2 | 80.9 | 12.7 | 0.34 | 0.20 | 65.7 | 14.1 | – | – | 72 |
Spathaspora passalidarum | UFMG-HMD-1.1 | 84.9 | 13.4 | 0.20 | 0.09 | 40.0 | 8.8 | – | – | 96 |
S. passalidarum | UFMG-HMD-14.1 | 91.0 | 13.1 | 0.18 | 0.10 | 36.0 | 9.5 | – | – | 96 |
Spathaspora sp. 1 | UFMG-XMD-16.2 | 72.9 | 7.9 | 0.23 | 0.10 | 46.0 | 9.3 | 0.57 | 18.2 | 96 |
Spathaspora sp. 2 | UFMG-XMD-23.2 | 68.6 | 6.4 | 0.22 | 0.08 | 42.4 | 7.2 | 0.61 | 17.1 | 96 |
Sugar consumption (%) – percentage of the initial D-xylose and glucose consumed.
Yp/s et (g/g) – ethanol yield: correlation between ethanol (ΔPethanol) produced and D-xylose and glucose (ΔSsugars) consumed.
Yp/s xy (g/g) – xylitol yield: correlation between xylitol (ΔPxylitol) produced and D-xylose (ΔSxylose) consumed.
Qp (g/L·h) – ethanol productivity: ratio of ethanol concentration (g/L) and fermentation time (h).
η (%) – fermentation efficiency: percentage of the maximum theoretical ethanol yield (0.51 g ethanol/g D-xylose and glucose).
Time when the maximum ethanol production (g/L) value was attained or time of the end of the fermentation experiment.