Lipase-catalyzed synthesis and antibacterial activity of N-vanillylnonanamide

N-vanillylnonanamide (VAN) was successfully synthesized from vanillylamine hydrochloride by enzymatic catalysis in supercritical carbon dioxide (SC-CO(2)). Five commercial lipases, Novozynne 435, Lipozyme IM, Amano PS, Amano G and Sigma Candida cylindracea type VII, as biocatalysts for VAN synthesis were compared. Lipozyme IM exhibited best yields of tested lipases. Various parameters such as time, temperature, pressure and vanillylamine hydrochloride/nonanoic anhydride ratio that influenced the reaction were investigated. Nonanoic anhydride showed the best acyl donor of the employed substrates. An amidation yield of 40% was obtained when nonanoic anhydride and Lipozyme IM were used at 170 bar and 50 degrees C for 23 h in SC-CO(2). Besides, addition of 2 mM divalent salts (CuCl(2) and ZnCl(2)) significantly increased 11-23% yield ofthe VAN. The enzyme operational stability suggested that Lipozyme IM maintained over 50 degrees C of the initial activity for the synthesis of VAN after reuse for 69 h. Furthermore, in vitro, VAN behaved as a potential antibacterial against Escherichia coli. (C) 2009 Elsevier B.V. All rights reserved