Insights into Genomic Characteristics and Biogenic Amine Degradation Potential and Mechanisms: A Strain of <i>Pediococcus acidilactici</i> Sourced from <i>Doubanjiang</i>

The control of excess biogenic amines (BAs) is crucial for the sustainable development of fermented foods. This study aimed to screen endogenous functional strains in <i>Doubanjiang</i> with the capacity to degrade BAs and to elucidate their application potential. <i>Pediococcus acidilactici</i> L-9 (PA), which was confirmed as a safe strain by phenotypic and genotypic analyses, exhibited an efficient degradation ability on BAs, particularly regarding tyramine. Notably, the degradation of tyramine was maintained at 24.03-50.60% at different temperatures (20-40 °C), pH values (4.0-9.0), and NaCl concentrations (3-18%, w/v). Additionally, genomic data revealed the presence of the laccase-coding gene, which was demonstrated to play a pivotal role in BA degradation by heterologous expression. Further, molecular docking results indicated that the degradation of BA by laccase is closely linked to the electron transfer pathway formed by the substrate and key amino acid residues. Finally, the degradation of tyramine by PA remained within the range of 8.19-64.19% under the simulated system with 6-12% salinity. This study provided valuable insights into the safety of PA and its potential degradation capacity on BAs, particularly in mitigating tyramine accumulation, which could improve the quality of <i>Doubanjiang</i> and other fermented foods.