Circular economy strategy to obtain chitin/chitosan as a plant growth promoter from black soldier fly

SALCEDO, M.F.; MESAS, F.A.; STOESSEL, M.N.; CASALONGUÉ, C.A.; MANSILLA, A.Y.

Mendoza

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

Chitosan is a deacetylated derivative of chitin that is the most abundant polysaccharide present in the fungal cell wall, insect, and crustacean exoskeletons from which it can be extracted. Mostly chitosans, at an industrial level, have been obtained from the shells of crustaceans due to their easy extraction, versatility, and high yields. However, currently, and because it fits in the policy of circular economy initiatives to obtain food and feed from bioconverter insects such as black soldier fly, Hermetia illucens are being studied. Our main goal was to evaluate the feasibility of black soldier fly grown on potato skins discarded by industrial foods as source of chitin/chitosan. Chitin was extracted from the adults and pupal exuviae of H. illucens by applying chemical methods, and converted into chitosan by homogeneous chemical deacetylation. Then, a fraction was subjected to a bleaching procedure using 5% H2O2 for 2 h at 70 °C, under stirring. Fourier-transformed infrared spectroscopy confirmed the identity of both the bleached (ChB) and unbleached (Ch) chitosan produced from H. illucens . The antioxidant properties of ChB were evaluated by the scavenging of 1,1-diphenyl-2-picrylhrazyl radical (DPPH) radical. On the other hand, we evaluated their biological properties as promoters of plant growth. Both Ch and ChB activate the auxin signaling pathway in DR5:GUS auxin reporter tomato plants. Moreover, when lettuce seedlings were supplemented with 10 μg/ml Ch and grown under nutrient-deficient medium an increase of approximately 75% and 40% in fresh and dry biomass, respectively were quantified. Total chlorophyll also increased by around 200% in Ch/ChC supplemented plants. Therefore, H. illucens can represent a new and sustainable alternative of chitosan-based compounds for the horticulture field.