A Microbiological Method for the Determination of L-and D-Aspartic Acids.

Abstract

Two sets of conditions are described for the microbiological detn. of aspartic acid with Leuconostoc mesenteroides P-60. With one (incubation 39-42 hrs. at 35[degree]C in D-aspartic acid-containing medium of initial pH 5.5) only L-aspartic acid is detd. With the other (incubation 63-66 hrs. in L-asparagine-containing medium of initial pH 6.5) the total of L- and D-aspartic acids is detd. D-Aspartic acid is found by difference. Only very small amts. of D-aspartic acid (assumed result of slight racemization) were found in hydrolysates of casein and Lactobacillus arabinosus cells. Relatively large amts. of D-aspartic acid (2.15 and 3.36% of the protein) were found in hydrolysates of Streptococcus faecalis R and L. mesenteroides. Accurate recoveries of L- and D-aspartic acids added to either amino acid mixtures or hydrolysates were obtained.