Table 2.

Plackett–Burman experimental design for screening important variables for biomass production of Cordyceps militaris. Each variable was tested at two levels, low (-) and high ( +), and the effect of each variable on biomass production was examined in 12 experimental series

Run	Coded Values											Biomass (mg/100 mL)
	I	II	III	IV	V	VI	VII	VIII	IX	X	XI
1	1	1	-1	1	1	1	-1	-1	-1	1	-1	251 ± 1.80
2	-1	1	1	-1	1	1	1	-1	-1	-1	1	433 ± 2.00
3	1	-1	1	1	-1	1	1	1	-1	-1	-1	312 ± 3.12
4	-1	1	-1	1	1	-1	1	1	1	-1	-1	316 ± 1.73
5	-1	-1	1	-1	1	1	-1	1	1	1	-1	497 ± 2.20
6	-1	-1	-1	1	-1	1	1	-1	1	1	1	392 ± 2.50
7	1	-1	-1	-1	1	-1	1	1	-1	1	1	310 ± 2.30
8	1	1	-1	-1	-1	1	-1	1	1	-1	1	357 ± 2.78
9	1	1	1	-1	-1	-1	1	-1	1	1	-1	321 ± 2.64
10	-1	1	1	1	-1	-1	-1	1	-1	1	1	351 ± 3.60
11	1	-1	1	1	1	-1	-1	-1	1	-1	1	270 ± 1.73
12	-1	-1	-1	-1	-1	-1	-1	-1	-1	-1	-1	400 ± 1.32

I: Temperature (°C), II: pH, III: Inoculum size (% v/v), IV: Glucose (% w/v), V: Incubation period (days), VI: Yeast Extract (% w/v), VII: KH₂PO4 (% w/v), VIII: K₂HPO4 (% w/v), IX: MgSO4 (% w/v), X: NaCl (% w/v), XI: Dummy variable