Comparison of ultrasound and thermal pretreatment of Scenedesmus biomass on methane production

► Ultrasound and thermal treatments improved CH4 production of Scenedesmus ecosystem. ► Low energies applied led to floc formation while higher ones caused cell disruption. ► Different organic matter was released depending on the pretreatment used. ► CH4 production improved only when supplying high ultrasound energy and temperature.