A Bioinformatics-Driven Framework for Assessing Moringa Bioflocculants Against Waterborne Microplastics
Ali Khorakiwala and Nirupma Singh
29/09/2026
India houses 42 of the 50 most microplastically polluted cities in the world, and conventional coagulation removes only 1.8-54%. Conventional coagulation has shown variable removal efficiency for microplastics, motivating the investigation of natural coagulants such as Moringa oleifera cationic protein (MOCP). However, the molecular interactions between MOCP and plastic-associated chemical structures remain incompletely characterized. In this exploratory bioinformatics study, an MOCP structure with a reported isoelectric point of approximately 10–10.5 was obtained from the RCSB Protein Data Bank. Four representative polymer fragments were evaluated: polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS). Ligand structures were obtained from PubChem, blind molecular docking was performed using AutoDock Vina, and the highest-scoring poses were examined in PyMOL. The predicted Vina docking scores were −5.029 kcal mol⁻¹ for PET, −4.613 kcal mol⁻¹ for PS, −2.623 kcal mol⁻¹ for PE, and −2.163 kcal mol⁻¹ for PP. PET and PS therefore produced more negative docking scores than PE and PP under the applied protocol. The shortest measured contacts ranged from 3.5 to 4.2 Å and indicated geometric proximity in the predicted poses, but did not establish a specific interaction mechanism. Because isolated polymer fragments do not reproduce the size, weathering, additives, surface charge, or biofilms of environmental microplastic particles, these findings should be interpreted as preliminary computational predictions. They identify MOCP as a promising candidate natural coagulant for future particle-level experimental validation.