The current study investigated the efficiency of synergistic biological and Advanced Oxidation Process (AOPs) treatment (B-AOPs) using Aeromonas hydrophila SK16 and AOPs-H2O2 in the removal of Remazol Yellow RR dye. Singly, A. hydrophila and AOPs showed 90 and 63.07% decolourization of Remazol Yellow RR dye (100 mg L−1) at pH 6 and ambient temperature within 9 h respectively. However, the synergistic B-AOPs treatments showed maximum decolorization of Remazol Yellow RR dye within 4 h. Furthermore, the synergistic treatment significantly reduced BOD and COD of the textile wastewater by 84.88 and 82.76% respectively. Increased levels in laccase, tyrosinase, veratryl alcohol oxidase, lignin peroxidase and azo reductase activities further affirmed the role played by enzymes during degradation of the dye. UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and gas chromatography–mass spectroscopy (GC–MS) confirmed the biotransformation of dye. A metabolic pathway was proposed based on enzyme activities and metabolites obtained after GC–MS analysis. Therefore, this study affirmed the efficiency of combined biological and AOPs in the treatment of dyes and textile wastewaters in comparison with other methods.