Microalgae: The Next Best Alternative to Fossil Fuels after Biomass. A Review

It is expected that 84% of the global energy demands will be met through fossil fuels in 2030 due to increasing energy needs. However, due to their impact on the environment through the emission of anthropogenic green house gases, biofuels were introduced as alternative sources of energy. Biofuels of plant origin for the transport sector proved to be controversial due to competition for food production, fertile land and expensive production processes. As a secondary alternative, microalgae such as Scenedesmus obliquus, Chlorella vulgaris and Nannochloropsis sp. were found to be suitable candidates for liquid biofuels production. This review describes the production of transportation liquid biofuels from plant biomass and microalgae. Information is provided on how the controversies related to plant biomass lead to the use of algal biomass. The production processes involved in both generations are discussed and highlighted. Furthermore, details on the production of secondary products such as pigments, feed additives and valuable secondary metabolites are also provided.