This study explores carbon dioxide enrichment in anaerobic digestion to boost biomethane production and assess degradation kinetics and methanogenic pathway evolution. Carbon dioxide enrichment was found to improve inoculum digestion, supplying additional energy for methanogenic archaea. The methane yield of blank inocula increased by 53 % to 77 % after carbon dioxide enrichment. Although further digestion of inoculum residues took longer, rapid adaptation led to an increased methane …