OPTIMASI KONDISI PURIFIKASI PARSIAL, KARAKTERISASI DAN KINETIKA ESTERIFIKASI LIPASE Aspergillus niger 65I6 DARI SOLID STATE FERMENTATION PADA MEDIUM BUNGKIL JARAK

Extracellular lipase is an enzyme that catalyzes the hydrolysis reaction of triglycerides into free fatty acids and glycerol and synthesis reaction of esters. Lipase can be produced by microbes include bacteria, fungi and yeasts. Lipase by Aspergillus niger 65I6 produced in the medium of Jatropha cake using solid-state fermentation has a different character of the lipase produced by other microorganisms. The aims of this research was to determine the optimum condition partially purified lipase by Aspergillus niger 65I6 for characteristics. The methods of this research were conducted in 3 steps: (1) production of lipase, (2) partial purification using ion exchange chromatography, (3) characterization of lipases, including: pH, incubation time and temperature for optimum enzyme activity of lipase, stability temperature of lipase, organic solvents , molecular weight, lipase kinetics parameters (Km and Vmak). The results of this research showed that partial purification lipase by Aspergillus niger 65I6 using anion exchange chromatography esterification activity of 45.58 U/ml with specific activity of 421.97 U/mg adsorbed at pH 8 and 0.5 M NaCl elution.The enzyme gave the highest lipase activity when methanol used as a substrate. The optimum pH range for activity of lipase was alkaline pH ranges, about pH 8.0. The optimum temperature for activity of lipase was 40°C. The optimum incubation time for activity of lipase was 30 minutes. The enzyme was stable between at temperature range of 30-40°C. Partially purified lipase by Aspergillus niger 65I6 was 86.11% yield and purification factor 12,12. Km value of 0.27 mol/ml and vmax value of 52.63 mol/min/ml and a molecular mass of Lipase by Aspergillus niger at 19 kDa estimated by SDS-PAGE