Factorial Design to Optimize Biosurfactant Production by Yarrowia lipolytica

Table 3

Experimental design and results of the 2⁴ full factorial design for nitrogen source evaluation.

Run	𝑥^∗1	𝑥^∗2	𝑥^∗3	𝑥^∗4	ST^†	EI^‡
1	−1	−1	−1	−1	6.5	37.3
2	1	−1	−1	−1	14.5	26.1
3	−1	1	−1	−1	5.1	27.0
4	1	1	−1	−1	4.0	1.0
5	−1	−1	1	−1	16.6	45.3
6	1	−1	1	−1	22.0	52.2
7	−1	1	1	−1	19.5	40.6
8	1	1	1	−1	13.0	50.0
9	−1	−1	−1	1	7.5	35.7
10	1	−1	−1	1	6.0	30.6
11	−1	1	−1	1	9.3	13.0
12	1	1	−1	1	4.6	6.2
13	−1	−1	1	1	15.2	40.3
14	1	−1	1	1	16.3	50.1
15	−1	1	1	1	21.1	60.4
16	1	1	1	1	9.4	43.2
17	0	0	0	0	13.0	26.0
18	0	0	0	0	11.4	24.0
19	0	0	0	0	11.0	25.4

∗The coded variables 𝑥_𝑖 (𝑖 = 1, 2, 3, 4) are defined in Table 1. †Variation in surface tension (mN m⁻¹), ‡Emulsification index (%).