Antibiotic fermentation residue for biohydrogen production using different pretreated cultures: Performance evaluation and microbial community analysis.

Antibiotic fermentation residue produced from pharmaceutical plants has been listed as a "Hazardous Waste", however it contains various substrates which can be used for biofuel production. In this study, the possibility of biohydrogen production from antibiotic fermentation residue was evaluated, the process efficiency and microbial community dynamics with five different inoculum pretreatments (alkaline, γ-radiation, heat-shock, aeration and acid) were assessed. Results showed that alkaline pretreatment was most efficient for hydrogen fermentation, and the hydrogen yield, volatile solids (VS) removal and maximal hydrogen production rate reached 17.8 mL/g-VSadded, 17.8% and 3.79 mL/h, respectively. Different inoculum pretreatments led to a obvious variation in the fermentation pathway and microbial community structure. The highest content of hydrogen-producing bacteria, especially Clostridium, essentially contributed to the highest hydrogen fermentation efficiency for the system with alkaline pretreatment. This investigation suggested that antibiotic fermentation residue is a potential feedstock for hydrogen production through dark fermentation.