Biochemical characterization of a novel cold-active, halophilic and organic solvent-tolerant lipase from B. licheniformis KM12 with potential application for biodiesel production.

Nowadays, finding a talented lipase with high potency in biodiesel production has been attracted to researchers. In this study, an extracellular salt tolerant, cold-active and organic solvent-stable lipase producing bacterium was isolated from oil-contaminated environments located in Kerman province (Iran) and identified as Bacillus licheniformis KM12. Lipase was purified by 36.0% recovery and molecular weight was estimated about 33 kDa by SDS-PAGE. The optimal pH and temperature for lipase activity were found to be 8.0 and 35 °C, respectively. Lipase activity was remarkably increased about 37% after 20 min incubation at 20 °C. Km value of KM12 lipase was 0.53 mM for p-nitrophenyl palmitate (p-NPP) and maximum activity was detected for pNP-decanoate and glyceryl-decanoate substrates. KM12 lipase displayed significant stability in different organic solvents after 7 and 21 days of incubation, especially in polar organic solvents. Biodiesel production with 78% yields was achieved with the one-step addition of methanol at around 18 h by using Myrtus oil (as a non-edible oils feedstocks). These unique properties of KM12 lipase make it talented as a potential biocatalyst for biodiesel production.