Table 2.

Variables and their levels employed in Plackett-Burman design for screening of culture conditions affecting on oil degradation.

Variable code	Variable	Value
		−1	1
X1	Glucose	0.05	0.5
X2	Peptone	0.05	0.5
X3	Yeast-extract	0.05	0.5
X4	Ammonium chloride	0.1	1
X5	Calcium chloride	0	0.5
X6	Magnesium sulfate	0	0.5
X7	Arabic gum	0	0.1
X8	Triton X-100	0	0.1
X9	Fertilizer (K2HPO4+urea)	0	0.1
X10	pH	5	7
X11	Inoculum size	1	3