Table 5.

Experimental layout of the Box–Behnken design with coded independent variables, obtained response outcomes, and predicted response values.

	Unit	Low (− 1)	Middle (0)	High (+ 1)
X1: glycerol	g/L	10	55	100
X2: leucine	g/L	0.1	2.55	5.0
X3: phosphate	g/L	0.5	2.75	5.0
X4: urea	g/L	1	5.5	10

Run	Independent variables				Viscosinamide [g/L]
	X1	X2	X3	X4	Actual response	Predicted response
1	− 1	− 1	0	0	0.847	− 0.181
2	1	− 1	0	0	0.613	1.979
3	− 1	1	0	0	2.330	1.003
4	1	1	0	0	0	1.066
5	0	0	− 1	− 1	1.539	1.858
6	0	0	1	− 1	0.271	− 0.702
7	0	0	− 1	1	0.729	1.742
8	0	0	1	1	6.483	6.203
9	0	0	0	0	4.709	6.425
10	− 1	0	0	− 1	0	1.493
11	1	0	0	− 1	0	− 1.455
12	− 1	0	0	1	0.765	0.827
13	1	0	0	1	8.886	5.999
14	0	− 1	− 1	0	3.204	2.826
15	0	1	− 1	0	0	− 0.725
16	0	− 1	1	0	0.759	0.091
17	0	1	1	0	4.925	3.911
18	0	0	0	0	5.318	6.425
19	− 1	0	− 1	0	0.076	− 0.316
20	1	0	− 1	0	1.676	1.839
21	− 1	0	1	0	0.486	1.678
22	1	0	1	0	0	1.746
23	0	− 1	0	− 1	0	− 0.015
24	0	1	0	− 1	0	0.631
25	0	− 1	0	1	3.167	3.891
26	0	1	0	1	2.144	3.514
27	0	0	0	0	9.247	6.425