Factorial Design to Optimize Biosurfactant Production by Yarrowia lipolytica

Table 1

Experimental range and levels of the independent variables used in the 2⁴ full factorial design for the nitrogen source study.

Variable (g l^−1)		Level
	−1	0	1
Peptone (𝑥1)	0	6.4	12.8
Yeast extract (𝑥2)	5	10	15
Ammonium sulfate (𝑥3)	0	5	10
Urea (𝑥4)	0	0.1	0.2