KOH/g, and the water content was around 1%. This waste cooking condition will affect the worse bio-
diesel efficiency than fresh cooking oil. Figure 6 showed the best bio-diesel conversion efficiency form
waste cooking oil was around 93% in the conditions of 1.85 wt.% SrO, 6:1 methanol: oil molar ratio, and
3 minutes microwave irrational time. This situation was similar with Costa Neto et al. experimental result.