Degradation of Mycotoxins During the Production of Fuel Ethanol, Biogas, and Organic Fertilizer from Whole Grains

Abstract

During the production of fuel ethanol, biogas, and organic fertilizer from whole grains, mycotoxins in the feedstock raise complex issues regarding product safely. In fuel ethanol production, processes such as grinding, liquefaction, and fermentation can cause structural transformations or reductions in the levels of certain toxins (such as zearalenone and vomitoxin); however, degradation products may remain in the distillers’ grains protein feed, affecting the safety of the byproduct. During the biogas fermentation stage, anaerobic microbial communities can further degrade some toxins through enzymatic reactions and metabolic processes. The degradation efficiency is significantly influenced by feedstock characteristics, process parameters, and toxin types, and small amounts of toxins or their transformation products may still remain in the digested liquid. In the subsequent organic fertilizer production process, the high-temperature phase of composting helps reduce residual toxins, and the synergistic action of aerobic microorganisms enhances degradation. However, certain mycotoxins may not be completely degraded or may generate unknown metabolites, posing potential ecological and health risks after application to farmland. Elucidating the degradation mechanisms, transformation pathways, and product safety of mycotoxins during multi-stage sequential treatment is important for ensuring pollution control across the entire industrial chain and the safe utilization of resource-recycled products.