Biogas from microalgae: Review on microalgae's cultivation, harvesting and pretreatment for anaerobic digestion

The goal of this work was to give a comprehensive review on biogas production from microalgae biomass. Different process parameters were summarized in tables which could become comprehensive compendium of operation conditions of microalgae preparation for biogas production. Further,, the limitations of the process implementation and commercialization (e.g. high costs of implementation and maintenance, low biomass productivity, limited methane yield due to specific structure of microalgae cell wall) were discussed. It was concluded that the microalgae anaerobic digestion should be incorporated with production of other bioproducts such as biodiesel, bioethanol or volatile fatty acids. Such a biorefinery would open possibility to improve both wastewater treatment and generate valuable products from waste streams.