Lipase-catalyzed esterification of ferulic acid with lauryl alcohol in ionic liquids and antibacterial properties in vitro against three food-related bacteria

- Incorporation of aliphatic molecules into ferulic acid to ameliorate its oil-solubility.
- Design and synthesize a novel functionalized ionic liquid.
- The development of enzymatic esterification of ferulic acid in ionic liquid.
- Lauryl ferulate were assessed for the antibacterial activity against three bacteria.

Lauryl ferulate (LF) was synthesized through lipase-catalyzed esterification of ferulic acid (FA) with lauryl alcohol in a novel ionic liquid ([(EO)-3C-im][NTf2]), and its antibacterial activities was evaluated in vitro against three food-related bacteria. [(EO)-3C-im][NTf2] was first synthesized through incorporating alkyl ether moiety into the double imidazolium ring. [(EO)-3C-im][NTf2] containing hexane was found to be the most suitable for this reaction. The effects of various parameters were studied, and the maximum yield of LF (90.1%) was obtained in the optimum reaction conditions, in [(EO)-3C-im][NTf2]/hexane (VILs:Vhexane = 1:1) system, 0.08 mmol/mL of FA concentration, 50 mg/mL Novozym 435, 60 °C. LF exhibited a stronger antibacterial activity against Gram-negative (25  mm) than Gram-positive (21.5-23.2  mm) bacteria. The lowest MIC value was seen for E. coli (1.25 mM), followed by L. Monocytogenes (2.5 mM) and S.aureus (5 mM). The MBCs for L. Monocytogenes, S.aureus and E. coli were 10, 20 and 5 mM.