Catalysis Letters (2018) 148:831–842
Introduction of Two Halo-Alkali-thermo-stable Biocatalysts:
Puriﬁcation and Characterization
Leila Satari Faghihi
· Bagher Seyedalipour
· Gholamhossein Riazi
· Salman Ahmady‑Asbchin
Received: 29 October 2017 / Accepted: 3 January 2018 / Published online: 18 January 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2018
Halophilic bacterium, producing two extracellular proteases, was isolated from Badab-Sourt, Iran. 16S rDNA analysis shown
high similarity with the genera Idiomarina. Maximum secretion of enzymes was observed during the early-stationary phase
of bacterial growth. Both extracellular proteases were puriﬁed by three puriﬁcation steps; ammonium sulfate precipitation,
Q-Sepharose, and Sephadex G-200 chromatography columns. The molecular weight of puriﬁed enzymes was determined
by SDS-PAGE gel electrophoresis with approximate masses of 48 and 51 kDa (45.57 and 80.30 U/mg speciﬁc activity).
Proteases synthesized by strain S-18 were aﬀected by medium compositions. Optimum concentration of substrate, pH, and
temperature for both enzymes activity were 0.5% casein, 9.0, and 50 °C. However, puriﬁed proteases showed diﬀerent activ-
ity at various salt concentrations, which their maximum activity was determined in the presence of 7.5 and 5% NaCl. The
activity of enzymes increased in the presence of metal ions such as Mn
and decreased by the presence of Hg
. Both proteases were strongly inhibited by SDS, while DDT, EDTA, and 2-Mercaptoethanol could stimulate their
activity. The results of present research might be interesting issue for industrial applications and biotechnological processes.
Keywords Moderately halophilic bacteria · Idiomarina sp. · Badab-Sourt · Biotechnological processes · Protease
puriﬁcation · Proteolytic activity
During the past decades, proteases have been extensively
studied as an important group of industrial enzymes .
Due to the unique functions of proteases to catalyze proteins
hydrolysis processes, the investigation of proteases puriﬁca-
tion and characterization have been rapidly increased .
* Bagher Seyedalipour
* Salman Ahmady-Asbchin
Extended author information available on the last page of the article