The relevance of sustainability through circular economy has focused on exploring biomass for biofuels and subsequent reactor digestate waste valorization. This noble study has investigated the bio-hydrogen production from sugarcane bagasse fed membrane-less single-chambered microbial Electrolysis Cell (SC-MEC). Also, the consequent biochar production from the MEC reactor digestate to promote maximum energy extraction from waste was explored. The bagasse in MEC resulted in 0.25 m3 of hydrogen/m3/day at an externally applied voltage supply of 0.8 V, with coulombic efficiency (CE) of 82.87 +/- 2% and electrical energy efficiency of 97.47 +/- 2%. The cathode and the Shewanella sp. Enriched bioanode were arranged for overpotential reduction, resulting in a high current density of 62 A/m2. The bio remediation efficiency of SC-MEC was estimated in terms of COD removal reported as 31.16 +/- 0.5%, nitrate removal as 28.18 +/- 0.2%, and sulphate removal as 41.2 +/- 0.2%. The reactor digestate was pyrolyzed, and the biochar yield was calculated as 17.8 +/- 0.2%, with BET surface area of 8.903 m2/g. The fixed carbon content of digested bagasse was reported as 22.9 +/- 0.2, while the total carbon lost during microbial digestion in SC-MEC was around 32 +/- 0.2%. This study paves a route for a circular economy by practicing clean renewable energy and using the reactor waste for subsequent biochar production. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
