Obtaining and Characteristic of the Autolysate of Lactic Acid Bacteria

Abstract

Fragments of bacterial peptidoglycan relating to compounds of the muropeptide series have high biological activity. They have an immunological effect, due to the fact that they are signals for immune receptors and, accordingly, their activators. In order to obtain fragments of peptidoglycans, the autolysis of the bacterial mass Lactobacillus delbrueckii subsp. Bulgaricus 2–11 was performed and the characteristics of protein nature products of autolysate were given. To obtain cell suspensions at different growth stages, a growth curve of the bacterial culture was constructed for 48 hours. The autolysis of biomass was carried out at the end of the logarithmic phase of growth at the temperatures 37–90 0C and after the stationary phase of growth at the temperatures 37–90 0C for 7 days. The degree of autolytic changes was evaluated by the definition of colony forming units, the accumulation of amino acids, low molecular weight peptides and soluble protein in the autolysate. The results of studies of autolytic biomass changes have shown that the largest accumulation of amino acids occurs in autolysate, which was obtained at the end of the logarithmic phase of the growth of bacterial mass at exposures at 90 0C. The molecular-mass composition of protein nature compounds of the autolysate soluble fraction is determined. It is established that peptides with a molecular weight in the range corresponding to the molecular weight of the muropeptides are presented in the autolystate, but their quantity is rather insignificant.