Waste bio-based materials generated as by-products of palm oil mills have been successfully used as a heterogeneous catalyst in homogenizer-intensified biodiesel production. Palm bunch ash (PBA) contains potassium oxide as a major component that could catalyze palm oil to biodiesel at room temperature. The influential transesterification conditions such as ratio molar palm oil to methanol, rotational speed, catalyst weight and reaction time were investigated on biodiesel conversion. The highest conversion of 98.9% was obtained in presence of a ratio molar of 1:15, rotational speed of 4000 rpm, catalyst weight of 18 wt.% and 10 min reaction times. The catalytic stability test revealed that both catalyst amount and K2O concentration decreased after one reaction cycle. However, no calcination is required and the availability of PBA is abundantly in palm oil producer countries increasing its competitiveness to use as a heterogeneous catalyst. In addition, this process could save 6–98% of electricity consumption and 67–87% of reaction time compared to other methods.