Comparative Assessment of Biogas Production Potential of the Most Abundant Agro-residues in Turkey

Recent energy policies promote energy generations from green resources to meet sustainability criteria. Since Turkey is one of the largest agricultural producers globally, it has great biogas production potential. This study aims to evaluate the biomethane yields of the most abundant agro-residues in Turkey and to assess their potentials for contribution to biogas production. Within this scope, sunflower heads, tea residues, cotton stalks, and crop residues; wheat, rye, and triticale straws were collected from different regions of Turkey. Anaerobic batch digesters were conducted to investigate the biomethane production of the selected feedstock and operated for 30 days at 37°C. Each setup was conducted in triplicates and methane productions were monitored online. The main methane production route of the inoculum was determined as acetoclastic methanogenesis while Cloacimonetes, Firmicutes, and Bacteroidetes composed the core bacterial phyla. The greatest methane yield was observed in the digesters operated with the wheat straw followed (164 NmL/gVSinfluent) by triticale straw and sunflower head. The lowest yields were calculated for the digesters fed with the cotton stalks (71 NmL/gVSinfluent). To increase the biomethane potential yields in the anaerobic digesters operated with agro-residues and to make the anaerobic digesters more feasible, operational conditions should be optimized and physico-chemical and biological pre-treatment techniques and/or bioaugmentation applications should be integrated into the systems