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

Abstract

In the context of "Peak CO2 emissions & Carbon neutrality", H2 energy, as the green and clean energy, will make an important contribution to the carbon emission reduction and carbon neutralization. Bio-H2 production from organic wastewater achieved not only pollutants removal, but also the H2 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-H2 production from brewery wastewater in batch and semi-continuous fermentation. Appropriate initial pH 7.0 and organic loading of 21,173mg/L chemical oxygen demand (COD) (2670mg/L reducing sugar (RS)) stimulated the batch H2 fermentation efficiency with a maximum H2 yield of 1.89mol-H2/mol-RS and cumulative H2 production of 479.3mL/L. Comparing to the batch fermentation, semi-continuous fermentation showed significant improvement in H2 productivity and yield. The maximum cumulative H2 yield of 5.21mol-H2/mol-RS and production of 254.78mL were obtained with the optimal hydraulic retention time (HRT) at 47h after a 120h fermentation. This study demonstrated the potential of H2 production from brewery wastewater with C. butyricum, and a great improvement in H2 production in semi-continuous fermentation.