A simple, rapid and eco-friendly procedure was adopted to synthesize iron nano-catalyst (FeNCs) using the leaf extracts of Acalypha indica. The effectiveness of synthesized FeNCs was evaluated for the biogas production from mixed liquor volatile suspended solids (MLVSS). The FeNCs were characterized using UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy, Scanning Electron Microscope and X-Ray Diffraction. The catalytic activity of the synthesized additives of FeNCs during the anaerobic process showed a drastic reduction in the hydraulic retention time of 6days for biogas production 85-90%. This study also showed a significant increase in the total biogas production when MLVSS supplemented with 0.3 g/L FeNCs. The aforementioned additive yielded 0.345 (L/g volatile solids reduced) biogas which is relatively lesser (63%) when compared with the control 0.25 (L/g VS reduced) and their bulk salts 0.055 (L/g VS reduced).