Production of an extracellular thermohalophilic lipase from a moderately halophilic bacterium, Salinivibrio sp. strain SA‐2

Abstract

Fifty strains of moderately halophilic bacteria were isolated from various salty environments in Iran. A strain designated as SA-2 was shown to be the best producer of extracellular lipase and was selected for further studies. Biochemical and physiological characterization along with 16S rDNA sequence analysis placed SA-2 in the genus Salinivibrio. The optimum salt, pH, temperature and aeration for enzyme production were 0.1 M KCl, pH 8, 35 degrees C and 150 rpm, respectively. The enzyme production was synchronized bacterial growth and reached a maximum level during the early-stationary phase in the basal medium containing 1 M NaCl. Triacylglycerols enhanced lipase production, while carbohydrates had inhibitory effects on it. The maximum lipase activity was obtained at pH 7.5, 50 degrees C and CaCl(2) concentration of 0.01 M. The enzyme was stable at pH range of 7.5-8 and retained 90% of its activity at 80 degrees C for 30 min. Different concentrations of NaNO(3), Na(2)SO(4), KCl and NaCl had no affect on lipase stability for 3 h. These results suggest that the lipase secreted by Salinivibrio sp. strain SA-2 is industrially important from the perspective of its tolerance to a broad temperature range, its moderate thermoactivity and its high tolerance to a wide range of salt concentrations (0-3 M NaCl).

Halophilic Bacteria: Potentials and Applications in Biotechnology

“…strain SA-2. The maximum activity of the enzyme reported at pH 7.5 and 50 o C. The enzyme remained active in presence of 17 % NaCl (Amoozegar et al 2008 ). Marinobacter lipolyticus a novel moderate halophile was isolated from a hypersaline habitat with lipolytic activity that grow optimally at 7.5 % NaCl (Martín et al 2003 ).…”

Isolation, Identification and Extracellular Enzymatic Activity of Culturable Extremely Halophilic Archaea and Bacteria of IncheBoroun Wetland

“…Lipase activity was determined using MGM 23 % solid media supplemented with 1% Tween 80. After 21 days incubation production of opaque halos around the growth area was determined as a positive response [13]. DNA extraction, PCR amplification of 16S rRNA genes and sequencing Genomic DNA of archaeal strains were extracted using the Wanlam method and DNA of bacterial strains were extracted according to Marmur method with some modifications [14].…”

Comparison of Bacterial Biodiversity and Enzyme Production in Three Hypersaline Lakes; Urmia, Howz-Soltan and Aran-Bidgol

“…The plates were incubated at 34°C for 48 h and the blue colour zones around the bacterial growth was used to identify the lipase producing strains [16,17].…”