HYNES Erica Rut
Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci
GUILLERMO PERALTA; BERGAMINI CARINA; HYNES ERICA
BRAZILIAN JOURNAL OF MICROBIOLOGY
SOC BRASILEIRA MICROBIOLOGIA
Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in 21 strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including 15 mesophilic lactobacilli, four thermophilic lactobacilli,and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor.