Towards a circular economy in virgin olive oil production: Valorization of the olive mill waste (OMW) “alpeorujo” through polyphenol recovery with natural deep eutectic solvents (NADESs) and vermicomposting

Analysis of energy return on investment of dry anaerobic digestion for low water alperujo with oxidative, thermal and alkaline pretreatments

“…ALP use as a substrate for biogas production by WAD has been extensively studied on a laboratory scale (Borja et al, 1993; Boubaker & Cheikh Ridha, 2007; Bovina et al, 2021; Roig et al, 2006), but when the bioprocess is carried out on a larger scale, the high production costs and dependence on water make it an unsustainable alternative. Moreover, ALP contains 98% of the polyphenolic compounds ( PhC ) present in the olive fruit, a content that varies depending on the olive variety, the ripening of the stone fruit, the oil extraction system used and the storage time after extraction (Carmona et al, 2023; Solomakou & Goula, 2021). This is another feature that hinders the performance of ALP anaerobic digestion, since several works have reported an inhibitory effect of polyphenols on methanogenic bacteria (Bardone et al, 2014; Borja et al, 2003).…”