Formation of acidic carbonyl compounds by some homofermentative lactic acid bacteria.

and Staphylococcus aureus (Anderson et al., 1958); Brettanomyces schanderlii (Nelson et al., 1960), and the mold Absidia orchidis. The tendency of all microorganisms to contain similar amounts of these amino acids, coupled with the unlikely possibility of altering the amino acid composition of integral cell proteins, indicates that the use of microorganisms as concentrated sources of specific essential amino acids may be limited to those organisms which also produce amino acids extracellularly. The formation of such uncombined amino acids is more amenable to modification than is the formation of constitutive cellular amino acids. Further study of those organisms which form the greatest amounts of cellular amino acids may disclose strains which liberate the desired amino acids extracellularly. Such an organism would make a particularly valuable source of amino acids for feed supplementation.