Screening of enhanced biohydrogen production from anaerobic fermentation amended with nano-sized barium ferrite supported by aluminum oxide.

Anaerobic fermentation has attracted wide attention to effectively reduce carbon footprint and alleviate potential energy shortages, which is being regarded as a sustainable and promising technology to obtain high biohydrogen production from widespread organic wastes. However, biohydrogen commercial uptake is now dominantly inhibited by the low hydrogen yield and process instability. In this work, Al 2 O 3 /BaFe 2 O 4 nanoparticles (NPs) are successfully applied to anaerobic fermentation for investigating their effects on hydrogen yield, activity of bacteria and microbial community structure. The benefits of Al 2 O 3 /BaFe 2 O 4 NPs with respect to microbial metabolism, reactivity of enzymes and process optimization are systematically researched through batch experiments. In addition, various characterizations are used to verify the physical and chemical properties of Al 2 O 3 /BaFe 2 O 4 NPs. The results show that the activity of hydrogenases and microbe metabolism can be significantly inhibited by excess addition of Al 2 O 3 /BaFe 2 O 4 NPs (150 mg/L and 200 mg/L) while the optimum addition 100 mg/L of Al 2 O 3 /BaFe 2 O 4 NPs can boost the biohydrogen yield by 49% via facilitating microorganism growth and enhancing key enzymatic activities, which indicate that the Al 2 O 3 /BaFe 2 O 4 NPs display a beneficial influence on electron transfer efficiency and process stability. The existence of Fe3+, Al3+and Ba2+ derived from the corrosion of Al 2 O 3 /BaFe 2 O 4 NPs by organic acids synergistically improve the microbial transmembrane transportation and substrate utilization, which contribute to higher conversion rate of glucose into acetate, butyrate and H 2. Meanwhile, the complementary functions of Fe3+ and Al3+ can powerfully shorten the lag phase and promote the glycolysis, which finally accelerate the dark fermentation process. Compared with the control group, Clostridium _ sensu _ stricto _1 is selectively enriched by the addition of Al 2 O 3 /BaFe 2 O 4 NPs, which keep heavily involved in the synthesis of H 2. On balance, this study provides an effective strategy to enhance hydrogen productivity and maintain process stability, which offer the valuable information for the sustainable utilization of sewage sludge. [Display omitted] • Al 2 O 3 /BaFe 2 O 4 NPs are synthesized to enhance H 2 production. • Al 2 O 3 /BaFe 2 O 4 NPs show positive effects on activity of H 2 -producing bacteria. • The addition of Al 2 O 3 /BaFe 2 O 4 NPs can facilitate H 2 -producing bacteria growth. • Humic acids are reduced by addition of Al 2 O 3 /BaFe 2 O 4 NPs. • Firmicutes and Clostridium_sensu_stricto_ 1 are selectively enriched by Al 2 O 3 /BaFe 2 O 4 NPs. [ABSTRACT FROM AUTHOR]