Use of response surface methodology for the optimization of the lipase-catalyzed synthesis of mannosyl myristate in pure ionic liquid

• The enzymatic synthesis of mannosyl myristate in pure [Bmpyrr][TFO] was studied.
• This synthesis has been optimized by response surface methodology (RSM).
• A 33 full factorial design has been selected via Minitab® 16 for optimization.
• The resulting model predicted the best conditions leading to the highest yields.

The purpose of the present study is to find the conditions allowing to reach the highest 24 h-yield (24 h-η) for the synthesis of mannosyl myristate catalyzed by the immobilized lipase B from Candida antarctica (Novozym® 435) in the ionic liquid (IL) [Bmpyrr][TFO] (1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate). A full factorial design (FFD) was used in order to study the influence of three variables (temperature, mannose/vinyl myristate ratio and total substrate quantity) on the 24 h-η. This design led to a model based on a second order polynomial response function. The resulting predicted contour plots have shown that the highest 24 h-η should be obtained with high temperatures, low sugar/vinyl ester molar ratio and intermediate total substrate quantities (mmol). The model has been successfully verified and experimentally confirmed at the optimal conditions of 80 °C, substrate molar ratio of 1/10 and total substrate quantity of 0.26 mmol leading to the highest predicted 24 h-η of 72.2%.