Biohydrogen Production from Apple Pomace Waste

Abstract

Valorizing industrial waste into biohydrogen and organic acids is a promising approach for sustainable energy production and waste management. The objective of this study was to convert apple pomace, a lignocellulosic biomass, into biohydrogen and organic acids through batch fermentation. Ultrafine powder of apple pomace was subjected to heat-assisted extraction for 1 hour to obtain apple pomace hydrolysate. Fermentation was conducted using the hydrolysate (total sugar concentration = 51.05 g/L) with Clostridium tyrobutyricum in a 310 mL serum bottle for 6 days. Anaerobic condition was achieved by purging the bottle with high-purity nitrogen gas. Total gas production was measured daily using a gas-liquid displacement system, hydrogen percentage was determined by gas chromatography, and organic acids were analyzed by high-performance liquid chromatography. The results demonstrated a volumetric hydrogen production rate of 289.74 mL/L·day, and butyric acid production reached 5.29 g/L at the end of the fermentation. This study contributes to advancing the circular bioeconomy by transforming waste into valuable resources, thereby reducing reliance on fossil fuels and promoting sustainable industrial practices.