Preparation and Characterization of Lignin Microparticles-in-Alginate Beads for Atrazine Controlled Release

The use of lignin as polymeric matrices for controlled release systems in agriculture is a promising alternative for its revalorization. In this work, different atrazine delivery systems were studied. Lignin derived from ionic isolation was used for the preparation of atrazine-loaded microparticles by the solvent extraction/evaporation and microfluidic techniques. Microparticles were also encapsulated in sodium alginate beads. Lignin microparticles prepared by microfluidics presented a larger particle size, higher encapsulation efficiency and a narrow size distribution. The in vitro release of atrazine was evaluated in water. Atrazine release from microparticles prepared by the solvent extraction/evaporation technique showed a significant burst release, and this effect was reduced by incorporating microparticles within alginate beads. In addition, the phytotoxicity of the systems was evaluated employing Lactuca sativa seeds. The phytotoxicity results showed that lignin-based formulations are safe according to the parameters evaluated, in contrast with commercial atrazine that resulted phytotoxic.