Biodiesel and biohydrogen production from cotton-seed cake in a biorefinery concept

► We extracted the vegetable crude cotton seed oil from cotton seed cake (CSC). ► We produced biodiesel by alkaline reaction and characterized the final product. ► C. saccharolyticus showed good hydrogen production from the NaOH-pretreated CSC. ► The presence of oil in CSC and the use of Ca(OH)2 led to very low fermentability.