TURNING A THREAT INTO AN OPPORTUNITY: THE SALT TOLERANT INVASIVE SPECIES ACACIA SALIGNA AS A SOURCE OF BIOACTIVE PRODUCTS IN A BIOREFINERY APPROACH

This study explores the biotechnological valorization of the salt tolerant invasive species Acacia saligna (Labill.) H. L. Wendl., aiming for sustainable use within a circular economy framework. Biomass from leaves (including some inflorescences) and stems was collected, dried, ground, and sequentially extracted with solvents of decreasing polarity (water, methanol/acetone, ethyl acetate, dichloromethane, and n-hexane). Extracts were evaluated for total flavonoid (TFC) and phenolic content (TPC), allelopathic, and in vitro antioxidant activities (DPPH, ABTS, copper chelation, and FRAP). Enzyme inhibition was tested on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Residual biomass was analyzed for minerals, carbon, hydrogen, nitrogen, and protein content. Leaf extracts were richer in flavonoids and phenolics, with methanol/acetone extracts being the richest. Water extracts inhibited seed germination and growth of Lolium multiflorum and Lactuca sativa. Methanol/acetone stem extracts exhibited the highest antioxidant activity, while water stem extracts showed significant enzyme inhibition. The final residue contained low minerals but relevant protein content. Our results suggest that A. saligna extracts, especially methanol/acetone and water, are promising as bioherbicides, antioxidants, and cholinesterase inhibitors. The residue could be used for soil fertilization or to increase animal feed protein content. This study highlights the biotechnological potential of A. saligna biomass for sustainable and economically beneficial applications.