Table 6 Experimental range and levels used in central composite design matrix for ethanol production
From: Catalytic hydrolysis of agar using magnetic nanoparticles: optimization and characterization
Independent variables | Range and level | |||||
|---|---|---|---|---|---|---|
Symbol | − α | − 1 | 0 | 1 |  + α | |
(a) Escherichia coli K12 | ||||||
 Hydrolysate concentration (%) | X1 | 1.48 | 10.00 | 22.5 | 35.00 | 43.52 |
 Temperature (oC) | X2 | 27.61 | 30.00 | 33.50 | 37.00 | 39.39 |
 Time (H) | X3 | 1.30 | 3.00 | 5.50 | 8.00 | 9.07 |
(b) Saccharomyces cerevisiae S288c (ATCC 7754) | ||||||
 Hydrolysate concentration (%) | X1 | 1.48 | 10.00 | 22.5 | 35.00 | 43.52 |
 Temperature (oC) | X2 | 26.59 | 30.00 | 35.0 | 40.00 | 43.41 |
 Time (H) | X3 | 1.30 | 3.00 | 5.50 | 8.00 | 9.07 |