Abstract
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•Soybean fatty acids distilate (SFAD) was used for biolubricant production.•The esterification reactions using SFAD and polyols were catalysed by immobilized and non-immobilized lipases.•Non-immobilized lipases had good results for both alcohols, and immobilized enzymes (PMMA/PMMA) were more efficient with NPG.•Both immobilized and non-immobilized lipases (PMMA/PMMA) were reused in eight reactions.•Esters obtained from the reactions with non-immobilized lipases were evaluated for their phisicochemical properties.
The present work studied the synthesis of biolubricants from by-products of soybean oil processing using the lipase from Candida rugosa (CRL) both in free and immobilized forms, as biocatalysts. Soybean fatty acid distillate (SFAD) was used for first time as source of free fatty acids (FFA) to produce biolubricants via their enzymatic esterification with neopentyl glycol (NPG) and trimethylolpropane (TMP) alcohols in a solvent-free medium. The immobilization of CRL was performed via interfacial activation using a commercial hydrophobic support (Accurel) and a home-made core-shell matrix of poly(methyl methacrylate) (PMMA). Conversions of about 80 % were obtained using lyophilized CRL after 30 or 180 min using NPG and TMP, respectively. When CRL-PMMA/PMMA was used to catalyze the synthesis of NPG esters, 90 % conversion was achieved after only 6 h, whilst CRL-Accurel were more active using TMP. The biocatalysts maintained the reaction conversion during eight batches of 24 h. The lubricant properties of the products were also characterized, showing that it can be an environmentally friendly alternative for petrol lubricants