Screening of a Halobacteria Strain Producing Halophilic Lipase and Characterization of Crude Enzyme

Abstract:

A halobacteria strain Z4 producing extracellular halophilic lipase screened from Hypersaline lakes of Inner Mongolia was identified as Haloterrigena thermotolerans. The crude lipase from Z4 was partially characterized using p-NPB. The activity of crude lipase was markedly increased 20%~30% by metal ions (Ba2+,Fe2+,Cu2+), but was obviously decreased 20% by EDTA. The lipase was completely inhibited by PMSF. The activity and heat resistance of enzyme was increased by NaCl, suggesting that the enzyme has strong dependence and specificity on NaCl. The thermostability of the crude enzyme was increased by alcohols, the glycerin is the best one. The optimum conditions for the crude lipase hydrolyzing p-NPB were followed: 3.5 mol/L NaCl, 70°C and pH 8.0, and the optimum conditions for the crude lipase hydrolyzing p-NPP were followed: 2.5 mol/L NaCl, 80°C and pH 8.0.

Key words:Halophilic lipase, Halophilic archaeon, Identification, Characterization