Impact of critical parameters influencing enzymatic production of structured lipids using response surface methodology with water activity control

Water is an important factor in enzymatic reactions as it affects the enzyme activity and the equilibrium position of hydrolytic reactions. To study these effects, the authors first developed a system based on relatively simple and low-cost components that could continuously control the activity of water in organic media in a SpinChem® RBR.

Structured lipids with desired properties can be produced by enzymatic transesterification. This is a multistep reaction with many factors influencing both the product yield and quality. In this study, the single and combined effects of water activity, temperature and substrate ratio were studied on the reaction between high oleic sunflower oil and ethyl stearate.

The efficient mixing in the RBR also in viscous solutions such as oil, further improves the dispersion of nitrogen gas and the mass transfer rate.

A system to control the thermodynamic water activity in the range of 0.05–0.92 in a 0.12–0.3 L RBR from SpinChem® (Umeå, Sweden) was developed. A schematic drawing of the system is presented in the figure above. The reactor is a jacketed glass reactor (SpinChem® V2) with a rotating bed (SpinChem® S2) for agitation and compartmentalization of immobilized enzymes.