Toward developing more sustainable marine biorefineries: A novel ‘sea-thermal’ process for biofuels production from microalgae

•Addressing a novel strategy toward developing greener marine biorefineries.•Full assessment of the effects of the temperature and time in different aqueous media.•Seawater turned out to be an alternative medium for algae hydrothermal treatment.•Water salinity exerted different influences depending on the time and temperature.•Detailed conditions were found for liquid/solid biofuels and nitrogen-rich liquids.