Atoxigenic aspergillus flavus and peanut shell biochar for synergistic aflatoxin management in crops

Overview

Aflatoxin contamination caused by toxigenic Aspergillus flavus poses a serious threat to crop safety, farmer livelihoods, and export markets, particularly for peanuts and maize. This research proposes a synergistic biocontrol strategy that combines atoxigenic A. flavus strains with peanut shell biochar as a soil amendment. While atoxigenic strains have been used successfully in the United States and parts of sub-Saharan Africa, no registered product exists in India despite significant need. By pairing these beneficial fungal strains with locally sourced peanut shell biochar, the approach simultaneously targets toxigenic fungi and improves overall soil health, offering a sustainable, dual-benefit solution for pre-harvest aflatoxin management.

Technical specifications

Key features:

• Atoxigenic strain application — deployment of non-toxin-producing A. flavus strains that competitively displace toxigenic strains in the soil environment
• Peanut shell biochar amendment — utilization of agricultural waste-derived biochar to improve soil physicochemical properties, including structure, water retention, and nutrient availability
• Combined delivery system — biochar acts as a carrier and complementary soil treatment, creating a "double-edged sword" that addresses both soil health and aflatoxin contamination simultaneously
• Microbiome enhancement — biochar promotes beneficial soil microbial communities that further suppress toxigenic fungal activity
• Crop yield improvement — improved soil conditions and reduced fungal contamination contribute to higher pod yields in peanuts and related crops
• Molecular validation — planned investigation into the molecular mechanisms driving plant growth promotion and resistance to aflatoxin contamination

Technology readiness level

The individual components—atoxigenic A. flavus strains and biochar—have each been independently validated in field settings in the United States and sub-Saharan Africa, demonstrating efficacy in reducing pre-harvest aflatoxin contamination. However, the synergistic combination of these two components has not been comprehensively evaluated. Current research focuses on glasshouse and field validation of strain compatibility, determining optimal biochar dosage and application timing, and quantifying synergistic effects on soil properties, microbial flora, and crop yields compared to individual treatments. The approach is at the applied research and validation stage, with molecular-level mechanistic studies planned to support future product registration and commercial deployment, particularly in India where no biocontrol product for aflatoxin is currently registered.