1. Introduction
Biodiesel has been defined as “the mono alkyl esters” of long
chain fatty acids derived from renewable lipid feedstock, such as
vegetable oils or animal fats. Biodiesel can be used as a
substitute or an additive to diesel fuel. Compared to fossil-based
diesel fuel, biodiesel possesses many advantages such as cleaner
engine emissions, biodegradable, renewable and superior
lubricating property [1]. In spite of the many advantages of
biodiesel, it is not yet commercialized all over the world. The
major problem is the cost of the raw material. Biodiesel obtained
from neat vegetable oil is costly compared to the petroleum
diesel fuel. Waste cooking oil is a promising alternative to