CHARACTERISATION OF TRANSESTERIFICATION ON THERMOSTABLE LIPASE LK1 AS BIOCATALYST FOR BIODIESEL SYNTHESIS

• Main Author: Grebers Swend Sinaga, Luxy
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/87479
• Institution: Institut Teknologi Bandung

Lipase (EC 3.1.1.3) is a hydrolase enzyme widely used in industrial process, including biodiesel production. The main process in biodiesel synthesis is the transesterification reaction, converting triglycerides into methyl esters in the present of methanol with aids of a catalyst. Catalysts with solvent-tolerant and thermally stable are crucial as a biocatalyst in industry. One of catalyst is thermostable lipase. Compost lipase 1 (Lk1) is a thermostable lipase isolated from Pseudomonas stutzeri. The LK1 gene was inserted into the pET30a(+) expression vector and transformed into Escherichia coli host cells. Previous study showed low activity using high SDS concentration (10%). However, the use of the SDS at the above concentration likely caused enzyme denaturation. Therefore, this study optimized cell lysis with varying SDS concentrations to obtain soluble Lk1 protein. Additionally, Lk1 was characterized to gather information on its activity in the transesterification reaction as a biocatalyst. The results showed the optimum activity at concentration of 0.25% SDS. Purified protein using Ni-NTA affinity chromatography increased the specific activity of Lk1 up to four times higher compared than the crude extract. Further analysis showed that the enzyme protein prefer methyl palmitate (C16) as substrate at 60°C. The activity of enzyme increased by the present of n-hexane. This phenomenon was confirmed by in silico studies. The enzyme also exhibited transesterification activity using cooking oil. These results indicate that Lk1 has potential as a biocatalyst in biodiesel synthesis.