Particle Sizes-Dependent Antifungal Activity of Lignin Nanoparticles

In this study, lignin nanoparticles (LNPs) with solvent-antisolvent ratios of 1:10, 1:20, 1:30, 1:40 and 1:50 (v/v) show mean particle sizes of 220 nm, 130 nm, 80 nm, 55 nm and 20 nm after synthesised by nanoprecipitation method in an aqueous medium. Iodo-lignin nanoparticles (ILNPs) with solvent-antisolvent ratios of 1:10, 1:20, 1:30, 1:40, and 1:50 (v/v) show mean particles sizes of 360 nm, 230 nm, 85 nm, 75 nm and 40 nm synthesised by enzymatic catalysed iodination of LNPs. ILNPs exhibited excellent antifungal efficacy against various tested fungi such as Cunninghamella sp., Fusarium equiseti, Penicillium chermesinum, Aspergillus flavus, Aspergillus niger and Trichoderma piluliferum. The maximum antifungal activity was achieved by decreasing nanosize and increasing the concentration of both LNPs and ILNPs. LNPs demonstrated inhibition effects ranging from 63.34 % to 75.71 % against T. piluliferum, Cunninghamella sp., and A. flavus. ILNPs have a greater inhibition effect ranging from 86.33 % to 98.67 % against A. niger, A. flavus, Cunninghamella sp., F. equiseti, P. chermesinum, and T. piluliferum. This work has proven that LNPs and ILNPs are promising nano-fungicides for plant pathogenic fungi.