Factors affecting tyramine production in Enterococcus durans IPLA 655

Area of Science:

• Food Microbiology
• Biochemistry
• Fermentation Science

Background:

• Tyramine, a biogenic amine, is frequently found in fermented foods like cheese.
• Lactic acid bacteria can decarboxylate tyrosine, leading to tyramine formation.
• Controlling tyramine levels is crucial for food quality and safety.

Purpose of the Study:

• To investigate factors affecting tyramine production by Enterococcus durans IPLA 655.
• To determine the impact of carbon source, tyrosine, tyramine concentration, and pH on tyramine synthesis.

Main Methods:

• Cultivation of Enterococcus durans IPLA 655 in a bioreactor.
• Manipulation of carbon source, tyrosine, tyramine concentrations, and pH in the growth medium.
• Quantification of tyramine production under various conditions.

Main Results:

• Carbon source did not significantly affect tyramine production.
• Tyrosine was essential for tyramine synthesis; its presence inhibited production.
• pH exerted the most significant influence, with peak tyramine production at pH 5.0.
• Growth rate was reduced at the optimal pH for tyramine synthesis.

Conclusions:

• Tyramine production by Enterococcus durans is dependent on tyrosine availability and pH.
• Optimal conditions for tyramine synthesis involve specific pH levels (pH 5.0) and the absence of exogenous tyramine.
• Understanding these factors can aid in managing tyramine levels in fermented foods.