Cold-adaptation and alkaline hydrolytic proprieties of the polar streptomycetes prediction on plate assay, based on insoluble chromogenic substrates with azurine cross-linked

Abstract

A semi-qualitative screening based on protease and amylase activity evaluation in a basal agar medium
supplemented with insoluble chromogenic substrates based on AZCL (Azurine-Crosslinked with amylose
or casein) using a plate assay was used for selecting the polar streptomycetes able to produce cold
actives and alkaline amylases and proteases. This technique provides a specific and rapid simultaneous
detection of high active hydrolase producing strains based on the visible solubilization of small particles
of AZCL and the formation of haloes on plates. It has a great potential in increasing the efficacy of
screening streptomycetes able to produce hydrolytic enzymes. This study revealed the potential of the
selected streptomycetes isolated from polar soils to biosynthesize amylases and proteases cold-adapted at
low temperatures (from 5 to 20ºC) and alkaline pH values (8 to 9).