Optimization of Fermentation Conditions and Media for Production of Glucose Isomerase from Bacillus megaterium Using Response Surface Methodology

Table 5

The impact of variables and their interaction on glucose isomerase activity.

Y (enzyme activity)	Coefficient values	Stand errors	values
Constant	0.277	0.002	2.697 × 10^−13
X1	0.006	0.001	0.004
X4	0.012	0.001	7.016 × 10^−5
X8	−0.004	0.001	0.023
X1^2	−0.016	0.003	0.001
X4^2	−0.010	0.003	0.008
X8^2	−0.007	0.003	0.036
X1·X4	0.004	0.002	0.041
X1·X8	0.004	0.002	0.041
X4·X8	−0.000	0.002	0.942

Variables are encoded as follows: D-xylose concentration (X₁), yeast extract concentration (X₄), and cultivation temperature (X₈).