Aggregate removal of particulate matter by selective protein-rich fraction of Moringa oleifera extract

Particulate matter (PM) is microsized dust that occurs naturally and industrially; PM has harmful effects on humans and the environment by binding with heavy metal ions. This study showed that selective protein-rich Moringa oleifera seed extract (hereafter “Puri-Tox”) is an excellent aggregation inducer for the removal of PM. SEM, SDS-PAGE, protein quantitation and MS/MS sequencing were performed to characterize and analyze the Puri-Tox and PM aggregation efficacy. Puri-Tox (>25%) gradually aggregated PM in aqueous solution, with superior performance at pH 5–7 and below 60°C. Peptide sequence analysis revealed that short negatively charged and sulfur-rich peptides constructed a funnel-like structure, and these proteins seemed to act as enzymes to neutralize the charge of PM to induce mutual aggregation. These results can be used to develop products for the removal of PM from the human body surface or aqueous industrial waste.