Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel.

•Solvo-thermal in situ transesterification of SCG is introduced.•The solvo-thermal process induces the DCE hydrolysis leading to acid conditions.•The in situ induced acid catalyst enhances FAEE production from SCG.•Water in SCG is critical for maximizing acidity and FAEE yield.•FAEE yield is 11.8 wt% due to the DCE hydrolysis.