Abstract
Hydrogen has attracted significant interest as a sustainable energy carrier due to its high calorific value, high octane number, and the production of water as the only combustion product. However, most hydrogen is produced via steam methane reforming, a process not enough environmentally sustainable. Dark fermentation (DF) is a promising and eco-friendly alternative to produce hydrogen via the microbial oxidation of organic substrates under anaerobic conditions. Among the microorganisms active in DF, Thermotoga neapolitana is particularly noteworthy as it achieves the highest hydrogen yields reported to date. This thermophilic bacterium can grow on a wide variety of sugar-based substrates - those derived from agro-industrial waste included – and produce hydrogen, acetic acid, and lactic acid. The present study aimed to identify the most suitable carrier for biofilm formation by T. neapolitana. A series of batch experiments was conducted to test various materials as solid supports, including polypropylene, polyurethane sponge, silicone (Tygon tubing), metal nets, and nylon nets. The nylon nets provided the best results and were used in further experiments in continuous stirred-tank reactors to assess their performance. Results provide valuable insights for the optimization of biofilm-based hydrogen production and the potential application of T. neapolitana in sustainable bioenergy processes.
