Biolubricant production under zero-waste Moringa oleifera Lam biorefinery approach for boosting circular economy

Abstract Here, we present a biorefinery perspective for biolubricant production with the valorisation of solid waste from Moringa oleifera Lam oil extraction (WMO). To achieve this, WMO, silica (SiO2), and a hybrid (SiO2–WMO) were prepared and employed as supports for the immobilisation of Candida rugosa lipase (CRL) via interfacial adsorption. The matrixes and immobilised biocatalysts were characterised by FTIR and AFM. The SiO2–WMO matrix was the most suitable, providing an immobilisation yield of 86 %. In the optimised conditions of esterification (40 °C, equimolar acid/alcohol ratio, and 22.6 mg/g of immobilised protein loading) in solvent-free medium, SiO2–WMO–CRL presented the best performance (94 % conversion) and retained its original activity after eight cycles. Furthermore, isoamyl esters exhibited physicochemical properties similar to those of commercial lubricants and could favourably be used as biolubricants in hydraulic machines and equipment. This pioneering work provides the opportunity for effective and cleaner production of biolubricants under a zero-waste Moringa oleifera Lam biorefinery approach.