Abstract
This study investigates the catalytic performance of calcium oxide (CaO) obtained from the Sokoto limestone site, which was used for the transesterification of non-edible tiger nut and sugar apple seed oils into biodiesel. The CaO catalyst was synthesized through thermal calcination and characterized with the aid of modern analytical tools, such as FTIR, XRD, TGA, and XRF. Under optimized process conditions. The result of the biodiesel yield was 91.8%. This shows that the catalyst demonstrated consistent activity over three reuse cycles and also proved its sustainability. These findings reveal that the potential of locally sourced CaO from the Sokoto limestone site is a viable, cost-effective catalyst for biodiesel production.