This study evaluated a novel three-stage process devoted to the cascade production of lactate, biohydrogen and methane from tequila vinasse (TV), with emphasis on attaining a high and stable biohydrogen production rate (HPR) by utilizing lactate as biohydrogen precursor. In the first stage, tailored operating conditions applied to a sequencing batch reactor were effective in sustaining a lactate concentration of 12.4 g/L, corresponding to 89% of the total organic acids produced. In the second stage, the stimulation of lactate-centered dark fermentation which entails the decoupling of biohydrogen production from carbohydrates utilization was an effective approach enabling stable biohydrogen production, having HPR fluctuations less than 10% with a maximum HPR of 12.3 L/L-d and a biohydrogen yield of 3.1 L/LTV. Finally, 1.6 L CH4/L-d and 6.5 L CH4/LTV were obtained when feeding the biohydrogen fermentation effluent to a third methanogenic stage, yielding a global energy recovery of 267.5 kJ/LTV.
- Dark fermentation
- Lactic acid fermentation
- Three-stage anaerobic digestion
García-Depraect, O., Muñoz, R., van Lier, J. B., Rene, E. R., Diaz-Cruces, V. F., & León-Becerril, E. (2020). Three-stage process for tequila vinasse valorization through sequential lactate, biohydrogen and methane production. Bioresource Technology, 307, . https://doi.org/10.1016/j.biortech.2020.123160