Fig. 7

Response surface plot (2-D) interaction effect expressed, respectively, in X1 and X2 axes. Here, inputs are 30 experimental runs carried out under conditions established by CCD matrix. EPS production as function with (A) nitrogen source (g L⁻¹) and carbon source (g L⁻¹) (B) carbon source (g L⁻¹) and pH (C) bacterial concentration and carbon source (mL L⁻¹) (D) nitrogen source (g L⁻¹) and pH (E) nitrogen source (g L⁻¹) and bacterial concentration (mL L⁻¹) and (F) pH and bacterial concentration (mL L⁻¹).