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Table 4 Coefficient of determination, optimal conditions and predicted and validated maximum values for different optimization criteria

From: Impact of cultivar selection and process optimization on ethanol yield from different varieties of sugarcane

Model (in coded form) R2 Optimal conditions Max. values
Temperature Time Prediction Value
5 X 55 = 77.15-3.77 T-4.12 t-5.64 T2 0.85 186 5 82.5 Na
6 X 70 = 82.33-4.80 T-2.50 t-6.15Tt-8.51 T2-5.94 t2 0.91 187 9 82.9 Na
7 X 74 = 78.99-2.20 T-2.99 t-4.88Tt-7.56 T2-5.50 t2 0.88 188 9 79.3 Na
8 X 120 = 76.18-8.00 T-7.02 t-6.01Tt-8.06 T2-10.66 t2 0.97 190 8 78.5 Na
9 G 55 = 38.05 + 3.63 T + 1.79 t-2.7 3 T2-2.91 t2 0.98 193 10 38.7 Na
10 G 70 = 34.99 + 2.73 T + 1.44 t-2.61Tt-2.61 T2 0.98 197 6 36.1 Na
11 G 74 = 26.54 + 3.24 T + 2.63 t 0.88 194 15 30.4 Na
12 G 120 = 27.67 + 2.25 T + 2.85 t-1.39Tt 0.97 198 14 31 Na
13 CSY 55 = 65.47 + 2.16 T + 1.04 t-4.90 T2-2.91 t2 0.96 189 10 65.3 65.8
14 CSY 70 = 63.73 + 1.80 T + 1.26 t-4.55Tt-5.29 T2-1.96 t2 0.99 188 11 63.5 64.5
15 CSY 74 = 52.67 + 3.05 T + 2.54 t-2.70Tt-2.85 T2-2.44 t2 0.95 189 12 53 52.7
16 CSY 120 = 49.24 + 0.35 T + 1.64 t-2.82Tt-2.19 T2-2.08 t2 0.92 192 12 49.7 50.3
  1. X, G and CSY stands for xylose recovery after pretreatment (% of theoretical), glucose yield after enzymatic hydrolysis (g per 100 g dry material) and combined sugar yield (g per 100 g dry material); subscripts (55, 70, 74 and 120) stands for substrates.
  2. T and t represents temperature and reaction time in coded form.
  3. Optimal conditions: Temperature (°C) and time (minutes); acid concentration was kept constant at 0.5% (w/w).
  4. Prediction. and Value stands for the maximum values predicted by the model and those obtained experimentally, respectively.
  5. Na means not determined.
  6. R2, coefficient of determination.