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P. Ghosh and U. Ghosh
of these factors were optimized for maximum decolorization of dye using Box–
Behnken statistical design (Box and Behnken 1960). Table 1 represents different
selected factors where each variable was tested in three different coded levels: low
(−1), middle (0) and high (+1). Table 2 represents a 29-trial of the experimental
design.
Table 1 Box–Behnken experiments design matrix with experimental and predicted values for dye
decolorization by laccase enzyme
Run Dye
concentration
(mM)
Laccase
concentration
(U/g)
pH HBT (mM) Observed
response (U/ml)
Predicted
response (U/ml)
1
8
100
5.5 1.0
26.3
26.29
2
4
80
5.5 1.5
36.4
36.35
3
4
80
6.5 1.0
33
32.52
4
6
100
4.5 1.0
57.7
56.65
5
6
80
5.5 1.0
85.3
85.94
6
8
80
4.5 1.0
29.6
31.10
7
8
80
5.5 0.5
37
36.53
8
4
60
5.5 1.0
24.8
24.31
9
6
60
4.5 1.0
51.2
50.59
10
6
60
6.5 1.0
63.6
64.13
11
6
100
5.5 0.5
63.6
63.37
12
6
80
5.5 1.0
86.3
85.94
13
6
80
6.5 0.5
68.6
68.95
14
6
80
4.5 1.5
68.2
67.36
15
6
80
5.5 1.0
85.5
85.94
16
4
80
5.5 0.5
32.2
31.86
17
6
80
5.5 1.0
86.3
85.94
18
8
80
6.5 1.0
35.7
35.98
19
6
60
5.5 0.5
54.2
54.64
20
8
60
5.5 1.0
33.6
32.48
21
6
80
4.5 0.5
57.1
57.36
22
6
60
5.5 1.5
68
69.25
23
6
100
5.5 1.5
55.86
56.44
24
4
80
4.5 1.0
25.8
26.53
25
6
100
6.5 1.0
53.9
53.99
26
6
80
5.5 1.0
86.3
85.94
27
6
80
6.5 1.5
67.4
66.64
28
8
80
5.5 1.5
39.9
39.72
29
4
100
5.5 1.0
25.8
26.42