Exploring the potential of cold-tolerant bacteria for production of biohydrogen

Abstract

The pursuit of sustainable energy solutions has led to significant interest in biohydrogen production through dark fermentation processes. Dark fermentation is a process in which organic wastes are utilized as substrates for biohydrogen-generating bacteria. Hydrogen gas, with its high energy content and water as its sole combustion byproduct, represents a promising energy source. This study investigates the potential of cold-tolerant bacteria isolated from natural and industrial environments for the fermentative production of biohydrogen, using fish processing residues and glucose as substrates. This approach aims to harness the dual benefits of waste management and biohydrogen generation offered by dark fermentation. Environmental samples were collected from various locations in Norway, including soil, marine sediment, and anaerobic sludge from an industrial biogas facility. In syringe-based biogas potential tests, biogas production was detected in nine out of ten environmental and industrial samples, with the highest production rate reaching 1.10 mL biogas per mL culture per day. A total of 209 bacterial strains were isolated from the collected samples, and 45 bacterial strains were selected for screening their biogas production capabilities. Among these, 13 strains were identified as biogas producers. Notably, Lelliottia amnigena (2VF05) demonstrated the highest hydrogen yield, achieving ≥ 0.5 mol H₂/mol glucose. In addition to identifying biohydrogen-producing bacteria, a lab-scale Up-flow Anaerobic Sludge Blanket (UASB) reactor was designed to facilitate future scale-up of the biohydrogen production process. The results of this study indicate that cold-tolerant bacteria, particularly Lelliottia amnigena, are promising candidates for sustainable biohydrogen production. Future research will focus on reactor testing and optimization for large-scale applications.