Heterologous Ectoine Production in Escherichia coli: Optimization Using Response Surface Methodology

Table 4

Estimated coded coefficients and p values for ectoine concentration (g/L) and bacterial productivity (mg ectoine/g cdw), optimized using response surface methodology.

Factor	Coded coefficient	value
Ectoine concentration (g/L)
Linear
X1	−0.0301	0.045
X2	−0.0313	0.039
Square
	−0.0556	0.004
	−0.0398	0.020
Interaction
X1X2	−0.0736	0.004
Productivity (mg ectoine/g cdw)
Linear
X1	−37.88	0.000
X2	−7.64	0.182
Square
	−6.03	0.312
	−12.80	0.054
Interaction
X1X2	−31.67	0.003

Significant, X₁ = OD value before induction, X₂ = the final concentration of inducer (IPTG).