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Characterization of thermo‐solvent stable protease from Halobacillus sp. CJ4 isolated from Chott Eldjerid hypersaline lake in Tunisia
Author(s) -
Daoud Lobna,
Jlidi Mouna,
Hmani Houda,
Hadj Brahim Adel,
El Arbi Mahdi,
Ben Ali Mamdouh
Publication year - 2017
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201600391
Subject(s) - halophile , protease , halotolerance , proteases , pmsf , serine protease , biology , food science , botany , microbiology and biotechnology , bacteria , chemistry , biochemistry , enzyme , genetics
About 110 newly isolated halophilic and halotolerant bacteria were screened for protease production. A moderately halophilic strain (CJ4), isolated from Chott Eldjerid Hypersaline lake in Tunisia, showed the highest activity on agar plate and was then selected. The biochemical and physiological characterization of the isolate along with the 16S rRNA sequence analysis placed it in the genus Halobacillus . Protease production was maximal at 120 g/L NaCl (2 M) and it started from the post‐exponential phase reaching a maximum level at the early decline phase of bacterial growth. Protease activity was optimal at 0.4 M NaCl, pH 9 and 45 °C. It showed an excellent stability over wide ranges of temperatures (30–60 °C), NaCl concentrations (0–5 M), and pH values (5–10), which make it a good candidate for industrial applications at harsh conditions. Crude protease was strongly inhibited by PMSF revealing the dominance of serine proteases. Protease activity exhibited high stability in the presence of several organic solvents and detergent additives. These findings make Halobacillus sp. CJ4 protease with a great interest for many biotechnological applications at high salt or low water content such as peptide synthesis and detergent formulation.