Enzymatic synthesis of citronellyl butyrate by lipase B from Candida antarctica immobilized on magnetic cashew apple bagasse lignin

Abstract

The enzymatic biotransformation of terpenic alcohols allows the selective production of new compounds with improved bioactivity. However, few studies are performed using enzymes mainly immobilized on natural material. In this context, Candida antarctica lipase B (CAL-B) was immobilized on lignin extracted from cashew apple bagasse conjugated with magnetic nanoparticles, and used in the synthesis of citronellyl butyrate. The immobilization process took place predominantly by adsorption and interfacial activation, followed by covalent bonds. The enzymatic load of 5 mgPROTEIN/gSUPPORT was chosen because it generated a catalyst (Lig-MNPs_CALB) with the highest catalytic activity (12.6 U/g) and yield of 71.5%. Lig-MNPs_CALB maintained 65% of its activity after 96 h of exposure at 50 °C and 73% after 60 days stored at 4 °C. In the synthesis of citronellyl butyrate by CAL-B in both forms, the optimal esterification conditions were 50 °C, 1:1 molar ratio (alcohol:acid), 10 mgPROTEIN/mL and 200 RPM. The esterification yield was higher in the process catalyzed by Lig-MNPs_CALB (96.4%) compared to catalyzed by free CAL-B (55%) at 24 h, and the Lig-MNPs_CALB maintained its activity for 10 cycles. Also, the antibacterial activity of citronellol in its esterified form has been improved, and citronellyl butyrate showed antifungal activity.