Table 5.

Central composite design and response values.

Run	Independent variablesa			Biomass (g/l)
	X1	X2	X3
1	-1	-1	-1	2.484
2	1	-1	-1	3.216
3	-1	1	-1	2.620
4	1	1	-1	3.486
5	-1	-1	1	2.896
6	1	-1	1	3.714
7	-1	1	1	3.196
8	1	1	1	3.892
9	-α	0	0	2.348
10	α	0	0	3.570
11	0	- α	0	3.354
12	0	α	0	3.650
13	0	0	- α	3.232
14	0	0	α	3.546
15	0	0	0	3.846
16	0	0	0	3.684
17	0	0	0	3.610
18	0	0	0	3.794
19	0	0	0	3.810
20	0	0	0	3.728

^aX₁, maltose; X₂, yeast extract; X₃, soytone.