Open Access

Lars Leonhardt, Julian Witt, Stefan Töpfl, Harald Rohm, Oleksii Parniakov

• In recent decades, the interest in algae species as a source of nutritive and valuable compounds has increased. This results from rising population growth, with serious effects in terms of land and water consumption, as well as greenhouse gases. Usually, extraction applications are focused on specific components, such as oil or pigments; however, conscious biorefinery of a broader spectrum of microalgal constituents would enable an increased economy. However, the technology for the production of microalgae is still within its early stages. The cultivation and downstreaming processes are highly energy- and cost-intensive, so the use of algae is limited to the production of high-value and low-volume products. Therefore, progression of environmentally friendly technologies is needed to realize an eco-friendly and economical usage of microalgae as a sustainable resource of the future. This chapter presents general overview of microalgae; moreover, origin and location of valuable compounds are discussed. Additionally, different conventional and novel (thermal and nonthermal) extraction techniques are reviewed.