Antimicrobial Sand via Adsorption of Cationic Moringa oleifera Protein

Abstract

Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.

Development of a low-cost water treatment technology using <italic>Moringa oleifera</italic> seeds

“…A modified method described in [13] was used to functionalize the three adsorbents with MOPE. MO solutions at concentrations ranging from 0.25 to 1.7 mg/ml were prepared by dissolving crushed MO seeds in deionized water and then shaking the solution continuously for 1 hour at room temperature.…”

“…The bacterial solution was diluted in phosphate buffer solution according to a procedure described in [13], to a final concentration of 10 3 -10 5 CFU/ml. Duplicates of 1 g each of sand, burnt rice husk, and activated carbon were incubated with MOPE and were washed vigorously to remove excess MOPE extract prior to the bacterial experiments.…”

Mini Review on Antimicrobial Activity and Bioactive Compounds of Moringa oleifera

“…The flocculating cationic polypeptide is another antimicrobial peptide isolated from the seed of Moringa oleifera and also referred as Flo or MOCP [21][22][23]. The flocculation cationic polypeptide showed antibacterial activity by damaging bacterial cell membranes and causing fusion between membranes.…”

Sulfonated Caspian Sea Sand: A Promising Heterogeneous Solid Acid Catalyst in Comparison with –SO3H Functionalized NiFe2O4@SiO2@KIT‐6

“…Grzesiak et al reported remediation of heavy metals from soil using quartz sand functionalized with organic amino silanes . There are also few articles on the antimicrobial sand particles prepared via surface modification, for example, with N ‐halamine acrylamidesiloxane copolymer, and cationic Moringa oleifera protein . Little attention however, has been paid to the application of functionalized sand as catalyst.…”