GABA-Producing Capabilities of <i>Lactococcus lactis</i> PL186 in Murine and Human

The novel strain <i>Lactococcus lactis</i> PL186 exhibits high GABA productivity <i>in vitro</i> and has demonstrated proven safety as a probiotic. In mice, this strain adheres to the intestinal mucosa, resulting in increased GABA levels in both serum and brain tissue. Additionally, <i>L. lactis</i> PL186 effectively colonizes the human gut and elevates GABA concentration in urine, highlighting its potential for systemic GABA enhancement. Oral administration of GABA-producing probiotics such as <i>L. lactis</i> PL186 therefore supports persistent endogenous GABA biosynthesis, helps maintain relatively stable systemic concentrations, and enables prolonged functional benefits. To our knowledge, this is the first report demonstrating that <i>L. lactis</i> can produce GABA that circulates within the human body.