Characterization of a Thermophilic Lipase from Bacillus licheniformis Ht7 Isolated from Hayran Thermal Springs in Giresun

摘要

In this study five thermotolerant bacteria were isolated from water and soil of the Hayran thermal springs in Giresun. These bacteria were identified as four Bacillus licheniformis (Bl-Ht1, Bl-Ht2, Bl-Ht5, and Bl-Ht7) and a Bacillus subtilis (Bs-Ht9) based on morphological, physiological, and biochemical characteristics, as well as phylogenetic analysis using 16S rDNA sequences. The strain Bl-Ht7 was exhibited the highest lipase activity, and the specific lipase activity was calculated as 15.916 U g-1. The maximum enzyme activity was exhibited at 90 oC and pH 9.0. The molecular weight was determined as approximate 22 kDa and it was confirmed using the zymogram analysis. The lipase activity was enhanced by the application of Ca2+, C 2+, Zn2+ ions, and some organic solvents but no important differences with the other applications. The optimal production time and suitable carbon source for the production of lipase were found to 24 h, and olive oil, respectively. The findings show that the temperature of the maximum enzyme activity is higher than the other known Bacillus lipases. The enzyme exhibited tolerance to high temperature, organic solvents, and metal ions, so it is attractive for industrial applications.