Salicylic acid loaded chitosan microparticles applied to lettuce seedlings: Recycling shrimp fishing industry waste.

Shrimp fishing industry wastes are still a main problem with high environmental impact worldwide. In this study, chitosan with ultra-high molecular weight and deacetylation degree ≥85% was obtained from shrimp fishing industry waste from Argentinean Patagonia. Chitosan based microparticles capable to entrap salicylic acid, a phytohormone known to play major role in the regulation of plant defense response against various pathogens, were prepared using TPP as crosslinker. Unloaded microparticles and microparticles loading several salicylic acid amount were fully characterized exhibiting a size between 1.57 μm and 2.45 μm. Furthermore, a good PDI, entrappment efficiencies from 59% to 98% and salicylic acid sustained release over 24 h were achieved. Chitosan based microparticles were non toxic in most of the doses applied in lettuce seedlings. Instead, microparticles can positively modulate plant growth and have the potential to improve plant defense responses. In particular salicylic acid loaded microparticles effect was very promising for its application as activators of salicylic acid dependent plant defense responses in lettuce as a model of horticultural plant species.