Isolation and Screening of Amino Acids Producing Bacteria from Milk

Twenty eight strains from buffalo and cow milk were tested for amino acids production in M-1, M-II and L-6 media, fourteen being from each source. Generally, bacterial strains did not produce significant amount of all amino acids, but bacteria from both sources produced aspartic acid and alanine in molasses media (M-I and M-II). Maximum production of aspartic acid (1.9 g L-1) was given by MB-7 and MB-12 in M-I medium after 72 h of fermentation. Some strains of both the sources also produced glutamic acid. Valine (maximum 1.4 g L-1 by MC-10) was produced in M-I medium by some bacterial strains isolated from cow`s milk only. In L-6 medium, lysine (maximum 1.8 g L-1 by MB-6 and MC-13) was produced by all the isolates of both sources. The other amino acid which was produced in L-6 medium by majority of strains was isoleucine (maximum 2.1 g L-1 by MB-6). MB-5 isolated from buffalo milk was found as the best strain in L-6 medium and its produced glutamic acid, lysine and alanine as 4.5, 1.3 and 5.1 g L-1, respectively. It was observed that bacterial strains isolated from buffalo milk were more productive than the strains obtained from cow milk. The strains MB-1, MB-5, MB-13 and MB-14 obtained from buffalo milk and MC-1, MC-7 and MC-13 from cow milk were selected as good amino acids producers strains. Thus aspartic acid, alanine, glutamic acid, lysine and isoleucine were the major amino acids produced from the bacterial strains of both the milk sources.