Mass Production of Microalgae in Photobioreactors for Biodiesel Application: Selection, Limitations, and Optimization

The algal biodiesel is produced in four steps: cultivation, harvesting and dewatering, lipid extraction, and transesterification reaction (converting lipids to fatty acid methyl esters, FAME, i.e., biodiesel). Microalgae cultivation in photobioreactor (PBR) is not only costly but also very challenging step among the steps of algal biodiesel production. In this chapter, the advantages and disadvantages of various types of PBR have been discussed in the context of mass production at outdoor conditions. Several environmental limitations which affect the performance of PBR are critically reviewed with respect to the selections of PBRs and microalgae strains. The mode of cultivation was found to affect the biomass and lipid productivity under different conditions. Thus, an overview suggesting the optimal ways to enhance the total lipid content of microalgae under different modes of cultivation is discussed in this chapter. The research work of microalgae cultivation on wastewater is tabulated and discussed in the context of feasibility of process. The quality of biodiesel strongly depends on the proportion of saturated and unsaturated fatty acids. Thus, various process parameters and strategies which affect the lipid’s composition are also discussed in detail.