Table 1: Design matrix and citric acid yield obtained after the fermentation process.

- Temperature Time pH Methanol Glucose Observed citric Predicted citric Residuals
Run order oC h conc (g/L) conc (g/L) acid yield (g/L) acid yield (g/L) (g/L)
1 25 10 5 24 3 12.33 12.30 0.03
2 30 40 6 60 4 11.77 11.73 0.04
3 30 40 3 60 7 12.20 11.77 0.43
4 30 110 3 60 4 10.36 10.19 0.17
5 30 30 3 60 4 10.28 10.21 0.07
6 40 40 3 60 4 13.18 11.91 1.27
7 25 80 2 96 6 12.97 12.71 0.26
8 25 10 2 96 3 13.28 13.50 -0.22
9 25 10 2 24 6 10.31 10.40 -0.10
10 35 80 5 96 6 10.23 9.73 0.50
11 25 80 5 24 6 12.38 12.31 0.07
12 30 40 0 60 4 12.10 12.12 -0.02
13 35 80 2 24 6 11.20 11.35 -0.15
14 25 80 2 24 3 14.29 14.05 0.25
15 30 40 3 60 1 12.66 12.42 0.24
16 35 10 2 24 3 11.69 11.77 -0.08
17 30 40 3 72 4 15.51 15.54 -0.03
18 35 80 2 96 3 12.74 12.87 -0.13
19 25 10 5 96 6 10.08 11.74 -1.67
20 20 40 3 60 4 10.26 10.55 -0.29
21 35 10 5 96 3 10.36 10.12 0.24
22 30 40 3 12 4 11.13 10.87 0.26
23 35 10 2 96 6 10.92 11.11 -0.18
24 30 40 3 60 4 10.46 11.08 -0.62
25 25 80 5 96 3 10.33 10.44 -0.11
26 35 10 5 24 6 13.02 13.06 -0.04
27 35 80 5 24 3 10.49 10.67 -0.18