[P008] Poster

1:00 PM - 1:50 PM JST(4:00 AM - 4:50 AM UTC)

[P04-466] Solid-state fermentation of Clostridium sp. bacteria supplemented with Chlorella vulgaris FSP-E as hydrolysate for biohydrogen production

○Jin Ruei Wu¹, Kuan Shiong Khoo¹ (1. Yuan Ze University (Taiwan))

Keywords:

Biohydrogen production,Solid-state fermentation,Dark fermentation,Clostridium sp.,Chlorella vulgaris FSP-E hydrolysate

The increasing accumulation of agro-industrial solid residues and the growing demand for sustainable energy have driven the development of efficient biological conversion technologies. Among these, biohydrogen production via dark fermentation has gained significant attention as a promising approach for renewable energy generation and waste valorization. In this study, biohydrogen production was investigated using solid residues as the primary substrate under solid-state fermentation (SSF), supplemented with Chlorella vulgaris FSP-E hydrolysate as an additional carbon source. Clostridium sp. was employed as the hydrogen-producing bacterium under strictly anaerobic conditions. Solid residues, particularly lignocellulosic and other complex organic wastes, often present limitations in microbial conversion due to their recalcitrant structure and low bioavailability. To overcome these challenges, Chlorella vulgaris FSP-E hydrolysate was introduced to supply readily fermentable organic compounds, including soluble sugars, amino acids, and essential nutrients. In addition, the inherent moisture content of the hydrolysate contributed to maintaining optimal water activity within the SSF system, eliminating the need for external moisture adjustment and avoiding energy-intensive drying processes. The SSF-based dark fermentation was conducted at 37 ± 1 °C to optimize the metabolic activity of Clostridium sp. Key operational parameters, including substrate composition, initial moisture content, inoculum size, and pH, were evaluated to enhance hydrogen production performance. The results demonstrated that Clostridium sp. effectively converted the available substrates into hydrogen through acidogenic pathways, primarily via acetate- and butyrate-type fermentation. The integration of microalgal hydrolysate significantly improved substrate accessibility and promoted microbial growth within the solid matrix. Hydrogen production performance was assessed in terms of cumulative hydrogen yield, production rate, and substrate degradation efficiency. The SSF system exhibited stable hydrogen production, although the rate was influenced by mass transfer limitations inherent to solid-state systems. Optimal moisture content was identified as a critical factor, as insufficient moisture restricted microbial metabolism, while excessive moisture reduced substrate porosity and limited gas diffusion. This study demonstrates the feasibility of producing biohydrogen from solid residues via SSF-based dark fermentation using Clostridium sp., with Chlorella vulgaris FSP-E hydrolysate serving as an effective substrate enhancer and moisture regulator. The findings highlight the advantages of SSF systems, including reduced water usage, improved energy efficiency, and enhanced process sustainability, providing valuable insights for the development of scalable biohydrogen production technologies.