Post-dewatering, the microalgae biomass can be used directly as a source of animal feed or human food. The cultural and economic development of society has resulted in changes in human lifestyles with developed countries’ diets highly caloric, rich in

saturated fats and sugars, with lower consumption of complex carbohydrates and dietary fibre. This has brought about a greater interest in new foods that can contribute to improve nutritional health and well-being (Plaza et al. 2008). Microalgae are certainly candidates for producing high protein (Spirulina), high carbohydrate (Chlorella) and high essential oil similar to fish oil (Diatoms). Fur­thermore, microalgae biomass can be converted to renewable fuels. The three different pathways that can be used to extract and convert microalgae wet biomass (20 % solid) into bioenergy are summarised in Fig. 1.2. To date, hydrothermal liquefaction seems to be the most energetically positive method for biofuel pro­duction from microalgae (de Boer et al. 2012). However, extensive research and development is still required to determine the most energetically favourable and economically feasible process for extracting and converting the algal biomass for renewable bioenergy.