Biodiesel is a mixture of fatty acid alkyl esters obtained typically by transesterification of triglycerides from vegetable oils, algal lipids, or animal fats. Transesterification of the lipid feedstocks is already a quite well-established chemical engineering process with a multiple-step reaction, including three reversible steps in series, where triglycerides are converted to diglycerides, then diglycerides are converted to monoglycerides, and monoglycerides are then converted to esters (biodiesel) and glycerol (by-product). One of the major challenges is to cost-effectively produce large quantities of lipids that can be readily harvested for biodiesel fuel production.

One of the approaches is to produce vegetable oils through Jatropha plantation. Chapter 23 reports the production of biodiesel and nontoxic jatropha seedcake from Jatropha curcas. The highest potential in biodiesel production probably resides in algae. The bio-oil (lipids) content for some of the algae can be upto 30-60% of its dry biomass, which energy density is at least as high as coal. Chapter 24 provides a quite comprehensive review of biofuels from microalgae towards meeting the advanced fuel standards. Chapter 25 discusses the bioprocess engineering aspects of biodiesel and bioethanol production from microalgae while Chap. 26 describes the arts of closed photo-bioreactors as tools for biofuel production. Chapter 27 reports extraction of hydrocarbons from Botryococcus braunii while Chap. 28 describes valorization of waste oils and animal fats for biodiesel production. Chapter 29 reports a single-step direct thermo-conversion of algal biomass to biodiesel with the formation of an algal char as potential fertilizer.