Salivary Mucin as a Source of Essential Amino Acids for the Lactobacillus Acidophilus (Hadley)

Abstract

It has been suggested that the mucin and mucinate contained in the dental plaque may serve as a source of nourishment for the organisms retained therein. This study was undertaken, therefore, to determine whether precipitated salivary mucin may serve as a source of essential amino acids for the L. acidophilus in a synthetic medium containing all the other known growth requirements for this organism. The findings show that precipitated salivary mucin, although rich in amino acids, is a poor replacement for tryptophane and/or casein hydrolysate in the Landy and Dicken medium which, when unmodified, is nutritionally adequate for the maximum growth of the Hadley strain of oral L. acidophilus. The value of precipitated salivary mucin as a source of essential amino acids for the test organism was substantially enhanced by the addition of crystalline trypsin and/or amylopsin to the test medium from which casein hydrolysate and/or tryptophane was omitted. Precipitated salivary mucin may serve as an efficient source of essential amino acids for the oral L. acidophilus in the presence of an exogenous source of proteolytic or amylolytic enzymes capable of hydrolyzing this glycoprotein.