Technology and Engineering of Biodiesel Production: a Comparative Study between Microalgae and Other Non-Photosynthetic Oleaginous Microbes

Microbial lipids are considered as a promising and sustainable feedstock for biodiesel production due to their fatty acid composition similar to that of vegetable oils. So far, microalgae have attracted more attention as a lipid producer in comparison to other non-photosynthetic oleaginous microbes. Nevertheless, recent studies showed the efficiency of other microorganisms, including bacteria, yeasts, molds which are able to accumulate lipids over 20 % of their dry biomass. Competence of lipid production by those photosynthetic and non-photosynthetic microbes are highly depend on the cost of reactor design, wide range of nutritional substrates, scalability, parasitic energy demand, metabolic function etc. Therefore, integration of biology and engineering is essential for a cost-effective production of microbial lipids. This paper compares microalgae and non-photosynthetic microbes as regards the factors affecting the techno-economical feasibility of the microbial oil production.