Enhanced Biodegradation Potential of Enterobacter ludwigii ES2 to Nicosulfuron Using Metabolomics Analysis, Functional Gene El-puuE, and γ-Aminobutyric Acid

Enterobacter ludwigii ES2 is a microorganism responsible for the efficient degradation of nicosulfuron. The reactive oxygen species generated by nicosulfuron were scavenged by the activated antioxidant system, increase in antioxidant enzyme activity, and upregulation of related gene expression, indicating how strain ES2 responds to nicosulfuron stress. Metabolomics analysis revealed that γ-aminobutyric acid (GABA) promoted the degradation of nicosulfuron by ES2, achieving a degradation rate of 98.78%. When the GABA aminotransferase gene, El-puuE, was knocked out, the degradation rate of nicosulfuron decreased by 40%. The protein El-PuuE was purified and expressed, followed by its modeling and molecular docking. This study lays the foundation for understanding the metabolic processes involved in microbial degradation of nicosulfuron.