High yielding and direct enzymatic lipophilization of ferulic acid using lipase from Rhizomucor miehei

• Ferulic acid was efficiently esterified with primary alcohols by R. miehei lipase.
• Yields were 76% and 88% for ethyl ferulate and decyl ferulate at optimized conditions.
• The syntheses of C3, C4, C6, C8, C14 and C18 ferulate esters were also successful.
• Short alcohols were preferentially esterified with ferulic acid by R. miehei lipase.

Ferulic acid is an abundant phenolic acid and a good antioxidant that occurs naturally in free form or esterified. The structure of this hydroxycinnamic acid, with a hydroxyl group in para-position, makes enzymatic esterification with lipases challenging. Adjusted lipophilicity of the ferulic acid as an antioxidant is crucial for complex food matrices, calling for a simple esterification method. Esterification of ferulic acid with ethanol and decanol in n-hexane using immobilized lipase from Rhizomucor miehei was optimized using surface response methodology. After 72 h, the yields were 76% and 88% for ethyl ferulate and decyl ferulate, respectively. Furthermore, ferulate esters of primary alcohols with varying chain lengths from C-2 to C-18 were also synthesized, with yields ranging from 76% to 92%. Finally, ferulic acid was preferably esterified to short chain alcohols in a mixture of primary alcohols. This study provides simple and efficient methods for the enzymatic esterification of ferulic acid.

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