Extracellular, Highly Stable, Alkaline Peptidases of the Alkalophilic Bacteria Alkalicaulis satelles G-192t and Aliidiomarina sp. P-156 and Their Possible Use in the Composition of Detergents

The peptidase activity of the alkaliphilic, aerobic, proteolytic bacteria Alkalicaulis satelles G-192T and Aliidiomarina sp. P-156 isolated from the system of hypersaline, alkaline Tanatar lakes (Altai Territory) was studied. Strains G-192 and P-156 710 were shown to hydrolyze para -nitroanilide substrates and exhibit the highest activity hydrolyzing of the aminopeptidase LpNa substrate. Analysis of partially purified peptidase preparations showed that the enzymes were most active and stablest in an alkaline pH range of 8.4–11. The peptidases of strains G-192 and P-156 were highly stable in NaCl up to 220 and 70 g/L respectively. The results of inhibitor analysis and the substrate specificity of the studied extracellular enzymes indicated their classification as metallopeptidases of the aminopeptidase type. The studied peptidases showed significant resistance to the surfactants Triton X-100 and SDS and the oxidizing agent H 2 O 2 . The isolated bacteria that produce peptidases can be used as a source of proteolytic enzymes in the development of new detergents.