ABSTRACT
Third-generation biorefineries use algae as feedstocks; fourth-generation biorefineries use genetically modified (GM) microalgae and, in general, GM microorganisms as feedstocks. The conversion of biomass into bioenergy and bioproducts is achieved through various processes, including (1) chemical conversion; (2) biochemical conversion, mainly through pretreatment, hydrolysis, and fermentation; and (3) thermochemical conversion through combustion, gasification, pyrolysis, or hydrothermal liquefaction.
Microalgal biomass, rich in carbohydrates and lipids, has excellent potential as a feedstock for producing biofuels such as biodiesel, bioethanol, biohydrogen, and biogas. Algae, in general, are a high-potential feedstock for producing food, chemicals, and materials.
