Photosynthetic biogas upgrading: an attractive biological technology for biogas upgrading

The future demands of transportation and industrial sectors necessitate groundbreaking research toward a sustainable energy source. Biogas from anaerobic digestion has been a well-studied research concept for the last two to three decades. The biogas technology suffers from the composition of unwanted contaminants (mainly CO2, H2S) in the production stream and utilization of cumbersome, energy-intensive removal technologies. The photosynthetic microalgae utilize the sequestered CO2 from biogas to synthesize different value-added products and aid biogas upgradation to attain the energy-rich biomethane. This chapter puts forth the positive attributes of photosynthetic microalgae-based biogas upgradation toward enhanced CO2 removal from biogas while meeting the natural grid system’s standards. Greater emphasis has been given toward photosynthetic biogas upgradation process set up, with possible integration with wastewater treatment and biomass production, the existing photobioreactors, influential process variables for better biogas upgradation, and discussion of the prospects of the photosynthetic biogas upgradation technology.