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Table 2 Hydrolysis and fermentation performance for the different process designs

From: Combining the effects of process design and pH for improved xylose conversion in high solid ethanol production from Arundo donax

  SSCF HYBRID SSCF HYBRID Hydrolysis
pH 5.0 pH 5.0 pH 5.5 pH 5.5 34°C
Hydrolysis performance      
Degree of glucan hydrolysis (%) 49.4 ± 0.8 54.2 ± 0.5 50.9 ± 3.8 54.0 ± 1.1 45.2 ± 0.3
Degree of xylan hydrolysis (%) 35.9 ± 2.7 43.0 ± 1.8 38.1 ± 5.3 43.3 ± 0.5 31.1 ± 0.6
Fermentation performance      
Ethanol yield (g/g consumed sugars) 0.42 ± 0.01A 0.43 ± 0.00 A 0.40 ± 0.02 A 0.39 ± 0.02 A -
Ethanol yield (% of theoretical) 81.7 ± 1.9 85.0 ± 0.1 79.3 ± 4.7 76.4 ± 3.5 -
Glycerol yield (g/g consumed sugars) 0.015 ± 0.002 0.031 ± 0.004 0.028 ± 0.004 0.039 ± 0.003  
Consumed xylose [%] 40.2 ± 3.8 33.7 ± 9.2 78.3 ± 2.0 55.8 ± 5.5 -
Xylitol production (% of consumed xylose) 32.0 ± 0.1 15.9 ± 0.2 25.5 ± 0.2 19.2 ± 0.4 -
Technical ethanol yield [%] 40.3 ± 0.7 A 45.2 ± 1.3 B 44.4 ± 0.4 B 42.7 ± 0.8 A B -
Calculated carbon recovery * (excluding cell growth) 0.93 ± 0.01 0.94 ± 0.00 0.92 ± 0.03 0.90 ± 0.02 0.96 ± 0.00
  1. *Carbon recovery calculated according to Eq. 5 in material and methods, with CO2 estimated based on ethanol production.
  2. Yields are based on the final (96 hour) values, and standard deviations are based on duplicate experiments. All statistically compared mean values are denoted with one or several letters (A, B). Values labeled with the same letter are not significantly different at a confidence level of 95%.