Bioactive peptides from okara for Fusarium plant disease control

Overview

This solution explores the valorization of okara, a byproduct of soybean milk processing, as a source of bioactive peptides for controlling plant diseases caused by Fusarium oxysporum and related Fusarium species. The research builds on the observation that soybean seeds naturally produce antimicrobial peptides during early germination to protect against soilborne Fusaria. By isolating and proteolyzing protein extracts from okara, the team has generated low molecular weight peptides that significantly reduce fungal growth and enhance plant defense responses.

In greenhouse pilot trials on tomato plants, application of the peptide extract to soil decreased Fusarium oxysporum disease severity by approximately 70 percent, while also fortifying plant growth and reducing vascular stress responses. The approach offers a sustainable, byproduct-derived alternative to conventional fungicides and contributes to circular economy goals in the soybean processing industry.

Technical specifications

Source material:

• Okara, the insoluble residue from soybean milk production, repurposed as a peptide feedstock
• Protein extract isolated from okara and proteolyzed into small molecular weight peptides

Antimicrobial activity:

• 60 percent reduction of Fusarium oxysporum growth compared with controls matched for inorganic component content
• Activity demonstrated in both liquid and solid culture setups

Plant protection performance:

• Greenhouse trials on tomato (cv Money Maker) showed approximately 70 percent reduction in disease severity
• Peptide treatment fortified plant growth and reduced vascular stress responses, suggesting modulation of plant defense pathways

Research approach:

• Iterative fractionation of peptide mixtures by charge, hydrophobicity, and size
• Identification of bioactive peptide sequences by mass spectrometry
• Testing of purified fractions against diverse Fusarium strains of different origins
• Greenhouse validation of purified fractions for protection against F. oxysporum race 1 on tomato

Technology readiness level

The technology is currently at an early to mid stage of development. Preliminary proof of concept has been established through published work demonstrating both in vitro antifungal activity and in vivo plant protection in small-scale greenhouse trials (10 plants, experiment repeated once). The next phase of research will focus on identifying the specific bioactive peptide or peptides responsible for the observed effects, purifying them for more targeted testing, and validating their efficacy across a broader panel of Fusarium strains and under controlled greenhouse conditions. The collaboration between the plant pathology laboratory and the biochemistry laboratory at Università degli Studi di Milano provides integrated expertise in fungal biology and peptide biochemistry to advance the work toward practical biocontrol applications.