Table 1.

The Plackett-Burman design experiment design matrix^a and experimental results.

Runs	Variables (g L−1)									OD660	Succinic acid production (g L−1)
	Glucose	YEb	CSLc	K2HPO4	KH2PO4	NaCl	MgCl2	CaCl2	MgCO3
1	80.0	15.0	15.0	1.5	3.0	1.5	0.3	0.6	40.0	7.9 ± 1.6 d	32.5 ± 1.0
2	50.0	15.0	15.0	1.5	3.0	1.0	0.3	0.3	60.0	4.2 ± 0.4	32.2 ± 1.3
3	80.0	10.0	15.0	1.5	1.5	1.0	0.6	0.6	60.0	6.2 ± 0.3	51.9 ± 4.8
4	80.0	15.0	10.0	3.0	1.5	1.0	0.3	0.6	60.0	9.3 ± 0.4	50.2 ± 3.1
5	50.0	10.0	10.0	3.0	3.0	1.5	0.3	0.6	60.0	2.6 ± 0.6	36.2 ± 0.6
6	80.0	10.0	10.0	1.5	3.0	1.5	0.6	0.3	60.0	6.7 ± 0.1	50.4 ± 1.5
7	50.0	10.0	10.0	1.5	1.5	1.0	0.3	0.3	40.0	5.9 ± 0.3	36.0 ± 0.2
8	50.0	15.0	15.0	3.0	1.5	1.5	0.6	0.3	60.0	2.9 ± 0.5	33.2 ± 1.2
9	50.0	10.0	15.0	3.0	3.0	1.0	0.6	0.6	40.0	5.3 ± 0.3	35.4 ± 1.2
10	80.0	15.0	10.0	3.0	3.0	1.0	0.6	0.3	40.0	9.1 ± 0.5	36.3 ± 0.6
11	50.0	15.0	10.0	1.5	1.5	1.5	0.6	0.6	40.0	10.0 ± 0.6	36.5 ± 2.7
12	80.0	10.0	15.0	3.0	1.5	1.5	0.3	0.3	40.0	6.3 ± 0.6	38.3 ± 0.7

^aThe two dummy was not shown in Table 1.

^bYE: yeast extract.

^cCSL: corn steep liquor.

^dStandard error was calculated from three independent samples.