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

Table 7

Analysis of variance (ANOVA) for the fitted second-order polynomial model for optimization of glucoamylase production.

Variables	Coefficient estimate	Sum of squares	Degrees of freedom	𝐹 value	𝑃 value
Model	11.65	38.9579	14	22.06	<0.0001
𝑍1	−0.48625	10.0955	1	44.98	<0.0001
𝑍2	0.260417	5.6745	1	12.9	0.002
𝑍3	0.294583	1.6276	1	16.51	0.001
𝑍4	−0.172083	2.0827	1	5.63	0.03
𝑍1𝑍1	−0.229896	0.1854	1	11.98	0.003
𝑍2𝑍2	−0.548646	5.5598	1	68.23	<0.0001
𝑍3𝑍3	−0.598646	8.3763	1	81.23	<0.0001
𝑍4𝑍4	−0.568646	9.2467	1	73.3	<0.0001
𝑍1𝑍2	−0.066875	0.0716	1	0.57	0.462
𝑍1𝑍3	0.021875	0.0077	1	0.06	0.809
𝑍1𝑍4	0.241875	0.9361	1	7.42	0.015
𝑍2𝑍3	0.445625	3.1773	1	25.19	<0.0001
𝑍2𝑍4	0.153125	0.3752	1	2.97	0.104
𝑍3𝑍4	−0.240625	0.9264	1	7.34	0.015
Residual		2.0185	16
Lack of fit		1.9431	10	15.46	0.002
Pure error		0.0754	6
Total		40.9763	30

𝑅²=95.07%, 𝑅²_Adj=90.76%, 𝑅²_Pre=72.44%, and PRESS: 11.29.