. 2019 May 2;9:6830. doi: 10.1038/s41598-019-43366-5

Table 1.

Analyzed Plackett-Burman design results with R² value of 0.9994.

Variable	Code	Level		Effect	Coefficient	Dry cell weight (g/L)
Variable	Code	+	−	Effect	Coefficient	T-value	P-value
Intercept				2.4375	0.007	347.13	0.000*
Glucose	G	10	2.5	−0.025	−0.016	−1.78	0.100
Fructose	F	10	2.5	0.161	0.081	11.51	0.000*
Yeast extract	Y	2	0.5	1.692	0.846	120.46	0.000*
NH₄Cl	N	1	0.25	−0.035	−0.018	−2.49	0.028*
KH₂PO₄	K	1.4	0.35	0.075	0.038	5.34	0.000*
K₂HPO₄	K2	0.6	0.15	1.145	0.572	81.53	0.000*
MgSO₄	Mg	0.6	0.15	0.065	0.033	4.63	0.001*
CaCl₂	Ca	0.05	0.0125	−0.108	−0.054	−7.71	0.000*
FeSO₄	Fe	0.006	0.0015	0.112	0.056	7.95	0.000*
Trace metals	T	x2	x0.5	0.032	0.016	2.25	0.044*
Vitamin	V	x2	x0.5	−0.038	−0.019	−2.73	0.018*

*Indicates statistically significant at 95% confidence level. Positive (+) and negative (−) levels of each parameter represent the concentration of variables in g/L.