Microalgal Biomass as an Alternative Source of Sugars for the Production of Bioethanol

Abstract

Ethanol is mostly produced by fermentation. The demand of ethanol as a renewabletransportation fuel has increased dramatically during the last decades. Thecurrent feedstocks for first generation bioethanol are sugar cane and corn kernels,in Brazil and USA, respectively. More recently, concerns regarding food securityand environment conservation promoted R+D+i of second generation (2G) bioethanolfrom lignocellulosic plant feedstocks. However, the complex structure ofthese materials poses a difficult-to-overcome barrier to a wider production of 2Gbioethanol. Thus, production of third generation (3G) bioethanol from photosyntheticmicroorganisms such as microalgae and cyanobacteria cultivated in aquaticfarms is increasingly considered a viable alternative according to higher productivitiesand simpler biochemical composition and structure in comparison withterrestrial crops. Strategies for cultivation, downstream processing for conversioninto biofuels, with emphasis in 3G bioethanol, and main drawbacks for technologydevelopments are discussed in this chapter.