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

2008; Wiley; Volume: 48; Issue: 3 Linguagem: Inglês

10.1002/jobm.200700361

1521-4028

Mohammad Ali Amoozegar, Ensieh Salehghamari, Khosro Khajeh, Mahbube Kabiri, Saied Reza Naddaf,

Algal biology and biofuel production

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 °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 °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 °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 thermoactiviy and its high tolerance to a wide range of salt concentrations (0–3 M NaCl). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)