Probiotic Bacteria as a Green Solution for Mitigating Zearalenone Toxicity and Pollution

Abstract

Distiller-dried grains with solubles (DDGS) are a valuable feed protein but are often contaminated with zearalenone (ZEN), a toxic mycotoxin affecting animal reproduction. This study investigates L-25 for ZEN removal from DDGS. Among 12 screened lactic acid bacteria, strain L-25 showed the highest removal rate of 45.5% for 10 mg/L ZEN within 24 h. Strain L-25, a Gram-positive, rod-shaped bacterium, was identified as Lactobacillus reuteri (PQ578323) through 16S rDNA analysis. The strain was tested for growth and ZEN tolerance, showing a 53.2% removal rate at 37°C and pH 7.0 with a cell concentration of 1×109 CFU/mL. Mechanistic studies revealed ZEN removal involves both bio-adsorption (44.4% from cell walls) and bio-transformation (16% from supernatant). FT-IR identified bio-adsorption sites as peptidoglycan in the cell wall, with a hydrophobic mechanism, while mass spectrometry confirmed no estrogen-active byproducts. Under optimal conditions (5% inoculation, 1:0.7 ratio, 37°C, 72 h), L-25 achieved a 53.70% ZEN removal rate in DDGS. In simulated gastrointestinal conditions, ZEN removal rates were 30.28% and 36.05%, demonstrating its effectiveness in a gastrointestinal environment. This study highlights the potential of L-25 for effectively removing ZEN from DDGS, offering a viable solution for improving feed safety. Its findings could drive advancements in mycotoxin management and enhance the quality of animal feed.