Effects of Zn 2+ and Mn 2+ on the photo-fermentative performance of HY01 in biohydrogen production from xylose fermentation

The addition of specific ions has a significant effect on the characteristics and kinetics of hydrogen production by photofermentation (PFHP). In this article, a new basic research investigated by us find that adjusting the addition ratio of Zn2+ and Mn2+ ions in the R. sphaeroides HY01 system can effectively improve their biohydrogen production from xylose. The largest biohydrogen yield can be obtained as high as 219.2 mL/g xylose at concentration levels of 12 mg/L Zn2+ and 8 mg/L Mn2+. The shortest lag time is 5.76 h, along with most of the organic energy in the substrate transferred to H2. To evaluate the effect of Zn2+ and Mn2+, the Gompertz model with appropriately modification is applied on the photosynthetic bacteria R. sphaeroides HY01, and the corresponding constants are obtained by fitting the model, which is of great guiding significance for the optimization of fermentation conditions.