RT info:eu-repo/semantics/article T1 Continuous two-stage lactate-driven dark fermentation process for enhanced biohydrogen production from food waste A1 Regueira Marcos, Lois A1 García Depraect, Octavio A1 Muñoz Torre, Raúl K1 Acidogenic fermentation K1 Dark fermentation K1 Hydraulic retention time K1 Lactate production K1 Organic waste K1 Volatile fatty acids AB The performance of a continuous lactate-driven dark fermentation (LD-DF) process based on the physical separation of lactate and hydrogen production was evaluated using simulated food waste (FW) as substrate. The optimum pH to maximize lactate production in the lactic reactor (LR) and the optimum hydraulic retention time (HRT) to maximize H2 production in the hydrogen production reactor (HR) were investigated. The lack of pH control in the LR implied a decrease in pH to values as low as 3.7, with the maximum lactate titer reached at a controlled pH of 4.5. The controlled reduction of the HRT from 12 to 4 h strongly affected the volumetric hydrogen production rate (HPR) in the HR. The stepwise reduction of HRT to 6 h resulted in the maximum recorded HPR of 9.6 ± 0.9 L H2/L-d, whereas a reduction to 4 h mediated a process collapse. The total consumption of lactate over carbohydrates in the HR suggested the occurrence of the LD-DF process at this stage. Principal component analysis (PCA) revealed a positive correlation between HPR and butyrate concentration in the HR. Additionally, HPR was negatively correlated with elevated levels of acetate and lactate in the HR broth. Overall, the application of a continuous two-stage LD-DF process allowed a significant reduction in HRT while maintaining high HPRs from FW. PB Elsevier SN 2214-7144 YR 2024 FD 2024 LK https://uvadoc.uva.es/handle/10324/73302 UL https://uvadoc.uva.es/handle/10324/73302 LA eng NO Journal of Water Process Engineering, noviembre 2024, vol. 67, 106116 NO Producción Científica DS UVaDOC RD 05-feb-2025