On the Cover

Many research teams are heavily invested in enhancing biomethane production from the abundant lignocellulosic wastes, striving to introduce more efficient pretreatment methods. To serve this purpose, in the September 2021 Issue of Biofuel Research Journal, a team at Brigham Young University (USA) tested the ability of the hyperthermophilic anaerobic bacterium, Caldicellulosiruptor bescii, to hydrolyze and solubilize lignocellulosic materials and thereby increase the production of biomethane by anaerobic digestion (DOI: 10.18331/BRJ2021.8.3.3). Several different wastes were tested to identify any potential toxicities, and none were found. Tests were run at lab-, bench-, and pilot plant-scale with C. bescii pre-digestion and mesophilic anaerobic digestion at 37-41°C. Biogas production by anaerobic digestion of C. bescii pre-digested dairy manure and waste activated sludge was approximately doubled compared with traditional mesophilic anaerobic digestion. The principal variables that must be quantified and controlled in engineering commercial, continuous-flow systems for waste disposal and biogas production incorporating C. bescii pre-digestion are the retention times in the anaerobic secretome bioreactor and the anaerobic digester. Incorporating C. bescii pre-digestion in an optimized commercial system is predicted to provide 75-85% volatile solids conversion to biogas with 75% methane when digesting dairy manure and sewage sludge. Achieving these results at a commercial scale requires optimizing retention times. Cover art by BiofuelResJ. ©2021.