Transesterification reaction between medium- and long-chain fatty acid triglycerides using surfactant-modified lipase

Area of Science:

• Biocatalysis
• Enzyme Engineering
• Lipid Chemistry

Background:

• Triglyceride modification is crucial for tailoring lipid properties.
• Lipase-catalyzed transesterification offers a green chemistry approach for lipid synthesis.
• Surfactant-modified enzymes enhance stability and activity in non-aqueous systems.

Purpose of the Study:

• To investigate the transesterification of medium-chain fatty acid triglycerides (MCT) and long-chain fatty acid triglycerides (LCT) using a surfactant-modified lipase.
• To determine the optimal reaction conditions for maximizing conversion and understand the reaction kinetics.
• To assess the stability of the modified enzyme under varying conditions.

Main Methods:

• Utilized a surfactant-modified lipase complex (lipase from Rhizopus japonicus and sorbitan monostearate) for transesterification in a nonsolvent system.
• Investigated the effects of water activity (A(w)), water content, and reaction temperature on the transesterification rate.
• Analyzed triglyceride composition using stochastic models and simulated kinetic changes.

Main Results:

• Achieved 74% conversion after a 48-hour reaction period.
• The triglyceride composition was accurately described by a 1,3-random 2-random stochastic model.
• Optimal enzyme activity was observed at a modified lipase A(w) of 0.35 and 0.09 wt% water content.
• The enzyme remained stable below 60°C, with activity decreasing above 70°C.

Conclusions:

• Surfactant modification of lipase enhances its efficacy in non-solvent transesterification of MCT and LCT.
• The reaction follows predictable kinetic and stochastic models, allowing for process optimization.
• Controlled water activity and temperature are critical for maximizing enzyme performance and stability in lipid modification.