Potential and characteristics of bio-H 2 production from brewery wastewater by a maltose-preferring butyrate-type producer: Investigation in batch and semi-continuous cultures.

In the context of "Peak CO ₂ emissions & Carbon neutrality", H ₂ energy, as the green and clean energy, will make an important contribution to the carbon emission reduction and carbon neutralization. Bio-H ₂ production from organic wastewater achieved not only pollutants removal, but also the H ₂ energy recovery and carbon emission reduction. In this study, a maltose-preferring producer of Clostridium butyricum NH-02 was investigated for the potential and performance of bio-H ₂ production from brewery wastewater in batch and semi-continuous fermentation. Appropriate initial pH 7.0 and organic loading of 21,173 mg/L chemical oxygen demand (COD) (2670 mg/L reducing sugar (RS)) stimulated the batch H ₂ fermentation efficiency with a maximum H ₂ yield of 1.89 mol-H ₂ /mol-RS and cumulative H ₂ production of 479.3 mL/L. Comparing to the batch fermentation, semi-continuous fermentation showed significant improvement in H ₂ productivity and yield. The maximum cumulative H ₂ yield of 5.21 mol-H ₂ /mol-RS and production of 254.78 mL were obtained with the optimal hydraulic retention time (HRT) at 47 h after a 120 h fermentation. This study demonstrated the potential of H ₂ production from brewery wastewater with C. butyricum, and a great improvement in H ₂ production in semi-continuous fermentation.
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