The main objective of the present work was to decolorize dye-containing wastewaters of textile industries using dye decolorizing bacteria which isolated from different aquatic samples. The most potent bacterial isolate capable of decolorizing malachite green with a decolorization rate of 97% within 48 h under aerobic conditions was selected for phylogenetic identification. The 16S rRNA amplification revealed that the isolate DB 8 was highly related to Alcaligenes aquatilis by 100%. The activity of lignin peroxidase responsible for malachite green decolorization was detected. The culture conditions for lignin peroxidase production by Alcaligenes aquatilis were optimized using response surface methodology. The optimal concentrations obtained were soluble starch, 10.2 (g/l); ammonium nitrate, 5.0 (g/l); KH₂PO₄, 2.0 (g/l); inoculums size, 10%; and time course, 36.6 (h) with optimized LiP activity of 5.6 U/ml.