Isolation and Characterization of the Trimethylamine (TMA)-Degrading Microbacterium lacticum Strain PM-1

Trimethylamine (TMA) is a common malodorous pollutant known for its detrimental effects on both the natural environment and human health. In this study, strain PM-1 was successfully isolated from activated sludge in a sewage treatment plant and identified as the first Microbacterium lacticum capable of degrading TMA. Strain PM-1 is characterized as a mesophilic and mild halotolerant bacterium, thriving within a temperature range of 20-40 °C and a salinity range of 10-80 g/L NaCl. The optimal initial TMA concentrations for strain PM-1 were determined to be 0.1 wt% under aerobic conditions and 0.05 wt% under anaerobic conditions. The strain demonstrated efficient TMA degradation rates of 98.02 mg/L/h aerobically and 4.44 mg/L/h anaerobically. Additionally, beef extract and peptone significantly enhanced TMA degradation and bacterial growth by 293% and 688%, respectively, under aerobic conditions. Microbacterium lacticum strain PM-1 is the first isolated Microbacterium lacticum with the ability to convert TMA. Further research will focus on its TMA degradation pathway through the identification of key enzymes and application in TMA-containing wastewater and exhaust gas.