Anaerobic Digestion of Microalgae: The Benefits of Digesting Microalgae Waste

The biodiesel production from microalgae seems to be a valuable alternative to meet the future energy requirements of the population; the high lipid productivity and the possibility of using no arable land and diverse sources of water provide several advantages over the current feedstocks used for biodiesel production. However, there are still some drawbacks which make the process scale-up economically unviable. The researchers have been focused on different areas of the process in order to reduce costs and increase profits; one of these areas is the additional energy recovery from the lipid-extracted waste. An increasing number of publications regarding methane production from microalgae waste have been published over the past five years; microalgae species, microalgae processing, pre-treatment application, operating condition in the digesters are some of the variables studied. This review attempts to summarise the results relative to the anaerobic digestion of lipid-extracted waste reported for more than 30 microalgae species in the last years, and some aspects which affects the process.