YtnP Lactonase: Expression, Characterization, and Potential for Biofilm Control in Membrane Systems.

Membrane biofouling remains a major bottleneck in filtration systems due to the limitations of conventional mitigation strategies. Quorum quenching (QQ) enzymes provide an eco-friendly alternative by disrupting bacterial communication required for biofilm development. YtnP lactonase from Bacillus luti T5 was cloned, expressed, and biochemically characterized. Sequence analysis and structural modeling confirmed its placement in the metallo-β-lactamase superfamily through the conserved HXHXDH motif. The enzyme's activity was further evaluated on nanofiltration membranes against a dual-species biofilm of Pseudomonas mandelii and Staphylococcus aureus. Biofilm formation inhibition on membrane surfaces was visualized using confocal laser scanning microscopy (CLSM), while extracellular polymeric substances (EPS) were characterized by Fourier transform infrared spectroscopy (FTIR). YtnP exhibited remarkable cold-active properties, maintaining catalytic efficiency even at 10 °C. When applied at 120 μg/mL, the enzyme inhibited over 90% of biofilm formation, as confirmed by CLSM. This study provides the evidence of the antibiofouling potential of YtnP in membrane systems, emphasizing its suitability for mild, energy-efficient filtration conditions.