The increased industrialization and motorization has led to a steep rise for the demand of petroleum products. Petroleum based fuels are obtained from limited reserves. It is estimated that the known crude oil reserves could be depleted in less than 50 years at the present rate of consumption. Hence, it is necessary to look for alternative fuels. An entire branch of biotechnology, referred to as "white biotechnology", centers on the bio production of fuels and chemicals from renewable sources. About 90% of the current biofuel market is represented by biodiesel and bioethanol. Biodiesel is an efficient, nontoxic, biodegradable and clean burning fuel alternative to petroleum fuels which runs in unmodified diesel engines. This paper reviews approaches to microbial synthesis of biodiesel, focusing on the role of synthetic biology as an enabling technology in the design of optimal cell factories.