Peptidase Activity of Proteinivorax Bacteria and Their Possible Ecological Role in the Microbial Communities of Tanatar Soda Lakes (Altai Krai, Russia)

Abstract

Peptidase activity of alkaliphilic anaerobic proteolytic Proteinivorax bacteria, P. tanatarense Z-910^T and P. hydrogeniformans Z-710^T, isolated from the Tanatar system of hypersaline alkaline lakes (Altai krai, Russia) was studied. Strains Z-910 and Z-710 were shown to hydrolyze para-nitroanilide substrates, exhibiting the highest activity hydrolyzing GlpAALpNA and LpNa. The peptidases were most active under alkaline conditions at pH 8–10 and were stable at temperatures of up to 50°C. The results on inhibitor analysis and substrate specificity of the studied extracellular enzymes suggested their classification as serine peptidases of the subtilisin-like type (strain Z-910) and metallopeptidases of the aminopeptidase type (strain Z-710).