Stimulation of Lactic Acid Bacteria by Substances Concomitant to Certain Proteolytic Enzymes

Abstract

A substance(s) accompanying partially purified unhydrolyzed trypsin, pepsin, pancreatin and erepsin exerted a pronounced stimulatory effect upon the growth and lactic acid production of Lactobacillus casei and Streptococcus lactis. These effects were observed in a synthetic medium and in milk. The active factor(s) did not appear to be an integral part of the enzyme, since crystalline enzymes possessed no stimulatory effect. Studies on lactalbumin, hydrolyzed with partially purified trypsin showed that the majority of the activity of such hydroly-sates was due to the factor(s) accompanying the enzyme rather than to products of protein cleavage. Further, preliminary studies indicated that a portion of the stimulation manifested by enzymatically hydrolyzed casein was due to the factor(s) associated with the partially purified enzymes.