Potential and characteristics of bio-H2 production from brewery wastewater by a maltose-preferring butyrate-type producer: Investigation in batch and semi-continuous cultures

In the context of "Peak CO2 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, semicontinuous 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.