Obtention of fatty acids and phenolic compounds from Colombian cashew (Anacardium occidentale) nut shells using pyrolysis: towards a sustainable biodiesel production

Sustainable management of non-edible agricultural residues of cashew nut production is a concern in Colombia. Therefore, this study aimed to study the fatty acid content of a pyrolytic liquid obtained from cashew nut shells (CNSs) from the Vichada region in Colombia. Trans-esterification of pyrolytic liquid was conducted to obtain biodiesel at the micro-scale as the first approach for this valorization route. Proximal analysis of samples was carried out using advanced analytical techniques (UHPLC-MS and CG-MS) whereas phenolic content and antioxidant activity were determined. The production yield of pyrolytic liquid was 69.15 & PLUSMN; 5.07% weight (wt.), at 550 degrees C and 2h of pyrolysis and the liquid was rich in fatty acids (-70% wt.) and long-chain phenols (-18% wt.). Among the phenolic compounds in liquid, mainly unsaturated C15:4 car-danol was identified (82.1 & PLUSMN; 5.5 mg/g), whereas the antioxidant activity of pyrolytic liquid was 0.714 & PLUSMN; 0.030 TE/g. Moreover, the biodiesel yield was 81% using catalyst sodium methoxide (12% v), and 50 degrees C and 26 min for the reaction. The obtained biodiesel in the hexane fraction was rich in methyl trans-8-octadecanoate (20.9 % wt.) and methyl palmitate (14.3 % wt.), being the representative compounds in the biodiesel. Therefore, the results indicated that thermal con -version of CNSs for obtaining biodiesel on a one-step process is a suitable strategy for the man-agement of toxic and non-edible cashew residues. Finally, this is the first work of its kind that propose in detail the composition of pyrolytic liquid obtained from Colombian cashew nut resi-dues under the proximate analysis approach and using advanced analytical techniques.