Lipid-dense and pre-functionalized post-hydrolysis spent coffee grounds as raw material for the production of fatty acid methyl ester

In this study, lipid-dense post-hydrolysis spent coffee grounds (PHSCG), containing ~23 wt% lipid, was utilized as feedstock in the production of fatty acid methyl esters (FAME) via in-situ (trans)esterification (ISTE). The collected PHSCG were pre-functionalized (~0.86 mmol H+/g dried, lipid-free PHSCG) after sufficient drying wet residues obtained from dilute hydrolysis (DAH) (SCG). Taguchi method and regression analysis adopted optimization ISTE, with temperature, solvent-to-solid ratio (SSR), reaction time, main factors investigated. An optimum yield 19.47 ± 2.44 g FAME/100 PHSCG, corresponding to ~96% conversion, could be achieved during ISTE a batch reactor system. lipids carried out without catalyst addition due inherent catalytic activity PHSCG. Elemental FT-IR analyses conducted determine extent functionalization. strong density material increased 21.5 times upon DAH. Although, some functionalized solubilized post-ISTE residue still had significant site, 2.47 native SCG, exhibited appreciable when used solid for esterification oleic methanol while having good stability. DAH subsequent induce simultaneous carbonization sulfonation, may means generating raw materials biodiesel lipid-containing lignocellulosic like SCG.