This book examines the background of fourth-generation biofuel production, use of genetically modified microalgae for production of fourth-generation biofuels; cultivation and harvesting of genetically modified microalgae; residue from biofuel extraction; health and environmental concerns of fourth-generation biofuels; regulations on cultivation and processing of the genetically modified algae; carbon dioxide sequestration; water footprint and current status and key challenges. The topic caters to academic researchers and industrial experts, who work in the field of biofuels as source of alternative fuel to achieve environmental and economic sustainability.