Valorization of Okara by Enzymatic Production of Anti-Fungal Compounds for Plant Protection

Abstract

Okara is a soybean transformation agri-food by-product, the massive production of which currently poses severe disposal issues. However, its composition is rich in seed storage proteins, which, once extracted, can represent an interesting source of bioactive peptides. Antimicrobial and antifungal proteins and peptides have been described in plant seeds; thus, okara is a valuable source of compounds, exploitable for integrated pest management. The aim of this work is to describe a rapid and economic procedure to isolate proteins from okara, and to produce an enzymatic proteolyzed product, active against fungal plant pathogens. The procedure allowed the isolation and recovery of about 30% of okara total proteins. Several proteolytic enzymes were screened to identify the proper procedure to produce antifungal compounds. Antifungal activity of the protein digested for 24 h with pancreatin against Fusarium and R. solani mycelial growth and Pseudomonas spp was assessed. A dose-response inhibitory activity was established against fungi belonging to the Fusarium genus. The exploitation of okara to produce antifungal bioactive peptides has the potential to turn this by-product into a paradigmatic example of circular economy, since a field-derived food waste is transformed into a source of valuable compounds to be used in field crops protection.

Antifungal Activity and Biochemical Profiling of Exudates from Germinating Maize Nostrano di Storo Local Variety

“…It is more likely that an interplay between endophytic bacteria and plant produced molecules, such as fatty acids, is the key to the resistance to pathogens attack. These molecules could not be the only actors in this interaction, peptides indeed could possess interesting antifungal properties [64], however with this experimental setup we did not analyze this aspect that will be addressed in future work.…”