Feruloyl esterase hydrolysis and recovery of ferulic acid from jojoba meal

There is growing interest in recovering ferulic acid from plant sources for use as feedstock for several high-value applications. Jojoba meal was examined as a potential source of ferulic acid. The feruloyl esterase domain of the Clostridium thermocellum cellulosomal xylanase was employed to hydrolyze ferulic acid from defatted jojoba meal. Esterase treatment produced 6.7 g of ferulic acid/kg of jojoba meal. The predominant source (86%) of the ferulate was found to originate from the meal's water-soluble simmondsin fraction. Seven feruloyl simmondsin species from jojoba meal were identified by liquid chromatography-mass spectroscopy. Only one species, a didemethylsimmondsin ferulate, displayed an enzymatic hydrolysis rate distinctly faster than the other feruloyl simmondsins. Complete hydrolysis of all feruloyl simmondsin species was achieved in 24-48 h at 60 °C with a 100:1 meal:enzyme weight ratio. Ferulic acid was efficiently recovered from the medium by ethyl acetate extraction. The recovered ferulic acid was readily converted to ethyl ferulate, demonstrating a facile procedure for producing a valuable product from defatted jojoba meal.