Effects of cultivation media and NaCl concentration on the growth kinetics and biogenic amine production of Lactobacillus reuteri

We analysed and compared the ability of four strains of Lactobacillus reuteri of sheep origin ranked as NSLAB (non-starter lactic acid bacteria) to grow and produce biogenic amines (BA) under cultivation conditions varying in cultivation media and salt content. The production of biogenic amines was primarily dependent on the growth rate of L. reuteri under particular cultivation conditions. From among produced BA, tyramine appeared as the dominant one while L. reuteri CCM 3644 possessed the most potent aminogenic ability. The influence of NaCl on the growth and production of BA was dependent on their concentration. Higher salt concentration (≥ 3% w/v) significantly inhibited the production of BA. On the contrary, the addition of 1-2% of NaCl w/v significantly improved the production of BA by three tested strains of L. reuteri (CCM 3642, 3644, and 3645). Finally, to better describe the production of BA over time, the relations between selected variables were calculated using linear regression. The appropriate fitting and the corresponding equations suggested the polynomial (degree 2) or exponential relations between the increasing concentration of NaCl and the concentration or calculated specific production rates of produced BA.