Fumonisin mycotoxins are a family of secondary metabolites produced by Fusarium verticillioides and related species, as well as some strains of Aspergillus niger. Fumonisin contamination of maize is a concern when grown under hot, dry conditions. When present above regulatory levels, there can be effects on animal health. New tools to reduce the toxicity of maize and maize products with high concentrations of fumonisin are needed. Recently, we reported an amine oxidase (AnFAO) from a fumonisin-producing Aspergillus niger strain capable of oxidatively deaminating intact fumonisins. In this study, AnFAO was used to reduce intact fumonisin concentrations in milled maize flour, whole kernel maize inoculated with fumonisin-producing Fusarium verticillioides, and dried distillers' grains with solubles (DDGS). The data showed that milled maize flour incubated with 1 µM AnFAO for 1 h resulted in complete deamination of FB1 and FB2. A greater than 90% reduction in FB1-3 concentrations was observed following a simple washing procedure of whole kernel maize in the presence of 1 µM AnFAO for 1 h. Similarly, a ≥86% reduction in FB1-3 concentrations was observed in DDGS after 4 h incubation with 1 µM AnFAO. Finally, we engineered the methylotrophic yeast Pichia pastoris to produce functional AnFAO in both a secreted and intracellular form. These results support the further development and application of AnFAO as a promising tool to remediate fumonisin-contaminated maize and maize products.
Keywords: Aspergillus; DDGS; Pichia pastoris; biotransformation; deamination; fumonisins; fungus; maize; monoamine oxidase; mycotoxins.