Optimum conditions for the formation of ammonia as a precursor of tetramethylpyrazine by Lactococcus lactis ssp. lactis biovar. diacetilactis FCl

To investigate the optimum conditions for the production of ammonia as a precursor of tetramethylpyrazine flavor compound from arginine by Lactococcus lactis ssp. lactis biovar. diacetilactis FCl, fermentation factors such as initial pH of culture media, fermentation temperature, concentration of arginine-HCI, and sugars were examined. The optimum conditions were initial pH 5.5 of the culture media, fermentation temperature of 34°C, 6% (w/v) of arginine-HCI, and 1% (w/v) of galactose as a carbon source. Under the optimum fermentation conditions, 40 mmole/l of ammonia was produced after 40 h.