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Table 4 Kinetic parameters for ethanol production by S. stipitis NRRL Y-7124 under SHF and SSF process after 72 h and 96 h respectively

From: Unraveling the structure of sugarcane bagasse after soaking in concentrated aqueous ammonia (SCAA) and ethanol production by Scheffersomyces (Pichia) stipitis

Parameters SHF SSF
Initial sugars (g/L) 19.52 27.95
Ethanol produced (g/L) 3.83 10.31
Cells produced (g/L) 3.57 n.d
Ethanol yield (g/g) 0.289 0.387
Fermentation efficiency (%) 56.80 75.88
Cells yield (g/g) 0.18 g/g n.d
Ethanol productivity (g/L/h) 0.239 0.214
Cells productivity (g/L/h) 0.0495 n.d
  1. n.d: not detected (Cells production was not detected in SSF). Fermentation was carried up to 72 h in SHF and 96 h in SSF. In SHF, maximum ethanol production (3.83 g/L) was observed after 16 h followed by a gradual downfall in conjunction with regular hike in cell mass production. After 16 hrs of fermentation, 13.32 g/l sugar was consumed. Ethanol yield, productivity and fermentation efficiency was calculated taking 16 hrs into consideration. Maximum cell mass (3.57 g/L) was recorded after 72 h. In SSF, yeast inoculum was added after 24 h of enzymatic saccharification (Pre-hydrolysis) and maximum ethanol production was obtained after 48 h of incubation. In SSF, after 48 hrs of fermentation, 26.6 g/l sugar was consumed by the yeast. Ethanol yield, productivity and fermentation efficiency was calculated taking 48 hrs into consideration. Fermentation efficiency (%) was calculated as the percentage of the maximum theoretical ethanol yield (0.51 g ethanol/g sugar used). The values are mean of three replicates. Standard deviation was within 10%.