Fig. 7

Three dimensions (3D) surface plots showing the relationship between the most significant factors and their effect on the decolorization of the dye. a 3D surface plot for the effect of yeast extract and nitrate concentration on the decolorization of Remazol black B by isolate B1. b 3D surface plot for the effect of yeast extract and dye concentration on the decolorization of Remazol black B by isolate B1. c 3D surface plot for the effect of yeast extract concentration and pH on the decolorization of Remazol black B by isolate B1. d 3D surface plot for the effect of dye and nitrate concentration on the decolorization of Remazol black B by isolate B1