Mixture of oligogalacturonides for the phytoextraction of heavy metals in contaminated soils

The mixture of oligogalacturonides (Ogal) allows the formation of bonds with heavy metals and modifies the distribution of Cu, Cd, and Fe metal cations in the soil, as well as attenuating the toxic effects on tomato seedlings, due to its high proportion of ionizable acid functional groups. Oligogalacturonides are constituted by a linear chain of galacturonic acid molecules linked by α-1-4 bonds. They are considered to be plant biostimulants. In the present work, the effect of an Ogal mixture on tomato (Solanum lycopersicum L.) plants was determined, which confirmed that they can be used to grow this and probably other species in soils with elevated levels of these metal cations. The application of the Ogal mixture in different forms and combinations modified the bioavailability of these cations in contaminated soil, favoring the phytoextraction process by tomato plants. Additionally, biomass production was stimulated without the plants showing visual symptoms of phytotoxicity. The results of this work offer an alternative for the use of the Ogal mixture in other hyperaccumulator crops to phytoremediate soils contaminated with heavy metal cations.