Available online 25 May 2022

Esterification of unmodified fatty acids to underivatized fructose in low-solvent media (<10%) was achieved.

Higher yields were obtained in Novozym® 435 esterification systems using tert-butanol and DMSO co-solvents.

Ball-milling of fructose crystals enhanced polar substrate availability by enlarging its surface area.

Hydrophobicity of Novozym® 435 favoured esterification in low-solvent media.

Two thirds of the acylation occurred during the first stage of the low-solvent reaction by mechanical ball milling of carbohydrate substrate.

Synthesis of carbohydrate fatty acid esters catalyzed by immobilized lipases is a pathway to obtain specific isomers from renewable feedstock, compared to unselective chemical esterification. While the use of low-solvent reaction media (≤ 10%) offers advantages, the interactive effects of these media with biocatalysts and substrates should be modulated towards high catalytic efficiency and substrate availability. Among the investigated co-solvents, tert-butanol and DMSO in a mixture of lauric acid substrate/co-solvent (90/10; v/v) resulted in high bioconversion yields using either Novozym® 435 or Lipozyme® RM IM, as biocatalysts. Increased hydrophobicity of the Novozym® 435 immobilisation support favoured bioconversion, while polar substrate surface area enlargement by ball-milling improved productivity through enhancement of fructose availability. A compromise between bioconversion yield (19.7%) and productivity (9.45 µmol/L min) was obtained in the reactions catalyzed by Novozym® 435 using ball-milled fructose at a concentration of 0.2 mol/L. Combining mechanical ball-milling of the substrates with low-solvent reaction media is expected to enhance and expand enzymatic synthesis of carbohydrate fatty acid esters.

carbohydrate fatty acid esters

evaporative light scattering detector

electrospray ionization tandem mass spectrometry

Carbohydrate fatty acid ester

Fructose laurate

Enzymatic acylation

Low-solvent biosynthesis

Ball-milling

© 2022 Published by Elsevier B.V.