This research addresses the development of environmentally sustainable natural rubber/styrene butadiene rubber (NR/SBR) composites incorporating a lignocellulosic biofiller derived from winemaking residues (WPL GS+101). To enhance interfacial compatibility between the inherently hydrophilic filler and the hydrophobic rubber matrix, a sequential surface modification strategy was employed: alkali treatment with 2 wt% sodium hydroxides (NaOH), followed by silanization using bis(triethoxysilylpropyl)tetrasulfide (TESPT) at various concentrations of 2%, 5%, and 10 wt%. Time-resolved alkali treatment was performed over durations of 1, 2, 3, 5, and 24 hours. The effects of surface modification were evaluated through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA).