Ultrasound assisted reverse micelle efficient synthesis of new Ta-MOF@ Fe3O4 core/shell nanostructures as a novel candidate for lipase immobilization.

In the present study, Ta-MOF@Fe3O4 core/shell nanostructures were synthesized in optimal conditions using the rapid, efficient, and novel ultrasound assisted reverse micelle method. FTIR, TGA/DTG, XRD, TEM, EDS and N2 adsorption/desorption isotherms were conducted in order to obtain samples with desirable properties. Results showed that the synthesized products had the thermal stability of 200 °C, particle-size distribution of 38 nm and surface area of 740 m2/g. Also, the VSM test showed that these compounds have desirable magnetic properties which provide the opportunity for recovery. Based on these obtained properties, final products were used as a novel candidate for enzyme immobilization. Results of SEM images revealed that the Bacillus licheniformis Km12 lipase is efficiently loaded on the Ta-MOF@Fe3O4 core/shell substrate. The stability test indicated the high stability of the enzyme loaded into these nanostructures. The synthesis method and the results obtained from enzyme immobilization developed in this study can be a new strategy for various applications of these novel compounds in diverse biological fields.

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.