Towards Sustainable Protein Recovery from Biological Waste: Assessing Polyethersulfone-based Microfiltration

Billions of tons of biological waste are generated annually. Despite containing valuable biomolecules, most remnants are discarded or recycled at a considerable cost. To help address this growing global issue, this study explored the reclamation of albumin from pre-waste biological fluids using 0.440 μm polyethersulfone (PES) membranes. Filtration efficiency was assessed under varying hydrodynamic conditions using discarded cell culture media - Dulbecco's Modified Eagle Medium (DMEM) and DMEM supplemented with Fetal Bovine Serum (DMEM + FBS). A membrane compaction process was performed before filtration to improve membrane uniformity. Nevertheless, statistical analyses revealed significant membrane-dependent variations in flow rate, with no consistent pattern tied to speed, suggesting that intrinsic membrane differences or experimental variability contributed to the observed variance. Microscopy confirmed non-specific particle retention, with higher recovery from DMEM samples than DMEM + FBS samples. Fourier Transform Infrared Spectroscopy (FTIR) identified protein-associated functional groups within the retained particles, suggesting that membrane fouling and absorption enabled protein retention despite the membrane's nominal pore size. In conclusion, these findings highlight the potential of microfiltration as a preliminary step in sustainable protein recovery from biological waste.