Production of an extracellular thermohalophilic lipase from a moderately halophilic bacterium, Salinivibrio sp. strain SA-2.
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).
Extremophiles Laboratory, Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran. amozegar@khayam.ut.ac.ir
Mohammad Ali
MA
Amoozegar
Ensieh
E
Salehghamari
Khosro
K
Khajeh
Mahbube
M
Kabiri
Saied
S
Naddaf
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D003470:Culture Media; D004269:DNA, Bacterial / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000302:isolation & purification; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007492:Iran; D007700:Kinetics; D008049:Lipase / Q000096:biosynthesis* / Q000378:metabolism; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011189:Potassium Chloride / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism; D012988:Soil Microbiology; D013696:Temperature; D014737:Vibrionaceae / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D014871:Water Microbiology
D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012965:Sodium Chloride; D011189:Potassium Chloride; D008049:Lipase