Abstract
It is well established that the performance of lipase B from Candida antarctica (CALB) as catalyst for esterification reactions may be improved by the use of ultrasound technology or by its immobilization on styrene-divinylbenzene beads (MCI-CALB). The present research evaluated the synthesis of butyl acetate using MCI-CALB under ultrasonic energy, comparing the results against those obtained using the commercial preparation, Novozym 435. The optimal conditions were determined using response surface methodology (RSM) evaluating the following parameters: reaction temperature, substrate molar ratio, amount of biocatalyst, and added water. The optimal conditions for butyl acetate synthesis catalyzed by MCI-CALB were: temperature, 48.8 °C; substrate molar ratio, 3.46:1 alcohol:acid; amount of biocatalyst, 7.5%; and added water 0.28%, both as substrate mass. Under these conditions, 90% of conversion was reached in 1.5 h. In terms of operational stability, MCI-CALB was reused in seven cycles while keeping 70% of its initial activity under ultrasonic energy. The support pore size and resistance are key points for the enzyme activity and stability under mechanical stirring. The use of ultrasound improved both activity and stability because of better homogeneity and reduced mechanical stress to the immobilized system.
Highlights
The use of lipases as catalysts for esterification reactions of short carboxylic acids has great interest because the esters obtained enzymatically may be labeled as “natural” [1]
The four variables were evaluated measuring their effects on the initial reaction rate for the ultrasound-assisted butyl acetate synthesis catalyzed by MCI-CALB
The 27 experiments for the central composite design (CCD) with their results are shown on Table 1
Summary
The use of lipases as catalysts for esterification reactions of short carboxylic acids has great interest because the esters obtained enzymatically may be labeled as “natural” [1]. An improved mixing of all reaction components might prevent the formation of an aqueous phase around the enzyme caused by a better dispersion of the carboxylic acids in the solvents, improving the enzyme performance. This improved mixing may be achieved by using ultrasound [10,11]. Few studies are found in the literature and scarce information is available on the mechanism(s) of ultrasound activation and its interaction with the enzymes and the immobilization supports
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
