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Production assay and partial characterisation of a protease produced by Idiomarina loihiensis, a moderatly halophilic bacterial strain
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1  Institut de la Nutrition, de l’Alimentation et des Technologies Agro-Alimentaires (INATAA), Université Frères Mentouri Constantine 1 (UFMC1), Route de Ain El Bey,25000 Constantine, Algérie
Academic Editor: Maurizio Ciani


Halophiles are a group of micro-organisms that live in saline and hypersaline environments and require salinity to survive in these extreme conditions. These micro-organisms are studied mainly for their biotechnological potential. The aim of this study was to characterise the phenology , to demonstrate the extracellular proteolytic activity of the studied strain Idiomarina loihiensis and production of a protease by batch fermentation in halophilic microorganisms.

Microscopic and macroscopic studies showed small Gram negative rods, forming small colonies (≤ 5mm) of domed spherical shape, regular contour, smooth surface, beige to opaque cream in colour. Protease production was studied under high salinity conditions by the moderately halophilic bacterium in basal media containing different nitrogen sources (glycine, peptone, gelatin, caseine, caseine peptone , triptone, skim milk, gelatin+ triptone); The effect of different nutrient sources, initial pH, temperatures, salt and thermal stability on proteolytic activity revealed that maximum activity occurred in media containing triptone and casein peptone as nitrogen source at pH 10, temperature 70 °C and 22. 5 % salts, and the thermostability result revealed that the protease was a thermostable enzyme.

Keywords: Key words: halophilic, protease, Idiomarina loihiensis, enzyme, proteolytic activity