Sequential Statistical Optimization of Media Components for the Production of Glucoamylase by Thermophilic Fungus Humicola grisea MTCC 352

Table 4

Ranges of the independent variables used in central composite design.

Symbol	Variable	Unit	Coded level
			−2	−1	0	1	2
𝑍1	Soluble starch	(g/L)	26.3	29.56	32.82	36.08	39.34
𝑍2	Yeast extract	(g/L)	7.45	8.34	9.23	10.12	11.01
𝑍3	K2HPO4	(g/L)	1.95	2.14	2.33	2.52	2.71
𝑍4	MgSO4·7H2O	(g/L)	1.7	1.84	1.98	2.12	2.26