Chapter 16: Biofuels from Microalgae

The development of renewable liquid fuels is essential for reducing the impact of the transport sector on the environment. To achieve this, photosynthetic microalgae offer a credible source of biomass that could potentially meet the volume demand of this sector. While much research effort has been invested in developing microalgal biodiesel, an economic process remains elusive. A more promising route is the thermochemical conversion of whole algal biomass, especially by hydrothermal liquefaction. This creates a viscous bio-oil that can be further upgraded into suitable hydrocarbon fuels. Although a host of research challenges remain, these processes utilise the whole biomass and remove the costly de-watering and extraction stages. As such, the thermochemical transformation of algal biomass offers a credible route to an affordable renewable transport fuel. This chapter reviews the chemical processing considerations of producing algal biodiesel and fuels from the thermochemical valorisation of algal biomass and discusses the remaining research challenges in this area.