AUTHOR=Cebrián-García Soledad , Balu Alina M. , Luque Rafael 

TITLE=Ultrasound-Assisted Esterification of Valeric Acid to Alkyl Valerates Promoted by Biosilicified Lipases

JOURNAL=Frontiers in Chemistry

VOLUME=6

YEAR=2018

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2018.00197

DOI=10.3389/fchem.2018.00197

ISSN=2296-2646

ABSTRACT=<p>A novel, environmentally friendly, and sustainable ultrasound-assisted methodology in the valorization of valeric acid to alkyl valerate using a biosilicified lipase from <italic>Candida antarctica</italic> is reported. This one-pot room temperature methodology of enzyme biosilicification leads to biosilicified lipases with improved activity and reaction efficiency as compared to free enzymes. Yields in the ultrasound-promoted esterification of valeric acid was ca. 90% in 2 h with 15% m/v of biosilicified lipase (Bio-lipase; 616 U/g <sub>biocatalyst</sub> enzymatic activity) and a molar ratio 1:2 (valeric acid:ethanol), slightly superior to that observed by the free enzyme (75% conversion, 583U/g <sub>biocatalyst</sub> enzymatic activity). The reuse of enzymes in these conditions was tested and the results show a relatively good reusability of these biosilicified enzymes under the investigated conditions, particularly preserving fairly stable specific activities (616 vs. 430 U/g <sub>biocatalyst</sub> after four reuses).</p>