https://doi.org/10.17113/ftb.56.04.18.5553 

Alkaline and Halophilic Protease Production by Bacillus luteus H11 and Its Potential Industrial Applications

Agnieszka Kalwasińska¹*, Urszula Jankiewicz², Tamás Felföldi³, Aleksandra Burkowska-But¹ and Maria Swiontek Brzezinska¹

¹Department of Environmental Microbiology and Biotechnology, Nicolaus Copernicus University, Lwowska 1, PL-87100 Toruń,
  Poland
²Department of Biochemistry, Warsaw University of Life Sciences, Nowoursynowska 159, PL-02787 Warsaw, Poland
³Department of Microbiology, Eötvös Loránd University, Pázmány Péter sétány 1/c, H-1117 Budapest, Hungary

Article history:
Received: 4 October 2017
Accepted: 4 September 2018

Key words:
Bacillus, proteolytic bacteria, alkalohalophiles, serine endoprotease, subtilisins

Summary:
This paper presents the results of the study on the production of protease by Bacillus luteus H11 isolated from an alkaline soda lime. B. luteus H11 was identified as an alkalohalophilic bacterium, and its extracellular serine endoprotease also showed an extreme alkali- and halotolerance. It was remarkably stable in the presence of NaCl up to 5 M. The enzyme was active in a broad range of pH values and temperatures, with an optimum pH of 10.5 and a temperature of 45 °C. It had a molecular mass of about 37 kDa and showed activity against azocasein and a synthetic substrate for the subtilisin-like protease, N-succinyl-L-phenylalanine-p-nitroanilide. The halo-alkaline protease produced by B. luteus H11 seems to be significant from an industrial perspective because of its tolerance towards high salinity and alkalinity as well as its stability against some organic solvents, surfactants and oxidants. These properties make the protease suitable for applications in food, detergent and pharmaceutical industries, and also in environmental bioremediation.

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