This research focused on the valorization of waste generated after tomato cultivation in Ecuador. Value-added products such as cellulose—abundant in stems and ideal for bioplastics—along with lignin and hemicellulose, were extracted. Tomato waste underwent physical pretreatments (washing, grinding, drying), followed by chemical processes including hydrolysis and bleaching. Multiple factorial experimental designs were employed to optimize the extraction process. For extractable removal, a 33 design identified optimal conditions: 96% ethanol, 300 mL of solvent, and 16.01 g of sample. Hemicellulose extraction (32 design) was most effective at pH 3.5 and 5.01 g. Lignin yield was maximized using 25 mL of sulfuric acid and 4 h of stirring. Cellulose extraction (33 design) yielded the highest amount (~ 1.3 g) using 17.5% NaOH, 100 mL, and 2 g of biomass. Biofilms were formulated using a 23 design to evaluate the effects of cellulose, PVA content, and drying time. Increasing PVA and cellulose improved film strength and homogeneity; drying time showed no significant effect. The best films exhibited low solubility in 99% acetone, permeability ranging from 2.68 × 10⁻20 to 8.93 × 10−20 Kg/Pa m s, and tensile strength of up to 8.01 MPa. These characteristics, along with good oil adsorption capacity, support their application as sustainable adsorbent membranes in wastewater treatment, aligning with circular economy principles. Additional analyses included solubility, permeability, tensile strength, thermal stability (TGA, DSC), and spectroscopic evaluation (FTIR) to identify functional groups in the lignocellulosic components. Results confirm the potential of tomato stem residues as a source of biopolymers for environmentally friendly materials.