title: Effects of light/dark cycle, mixing pattern and partial pressure of H2 on biohydrogen production by Rhodobacter sphaeroides ZX-5.
abstract: The effects of light/dark cycle, mixing pattern and partial pressure of H2 on the growth and hydrogen production of Rhodobacter sphaeroides ZX-5 were investigated. The results from light/dark cycle culture showed that little or no hydrogen production was observed during the dark periods, and the hydrogen production immediately recovered once illumination was resumed. Also, it was found that the optimum condition of shaking velocity was 120 rpm for hydrogen photo-fermentation. Meanwhile, shaking during H2 production phase (i.e., cell growth stationary phase) of photo-fermentation played a crucial role on effectively enhancing the phototrophic hydrogen production, rather than that during cell exponential growth phase. The other factor evaluated was hydrogen partial pressure in the culture system. The substrate conversion efficiency increased from 86.07% to 95.56% along with the decrease of the total pressure in the photobioreactor from 1.082×10(5) to 0.944×10(5) Pa, which indicated that reduction of H2 partial pressure by lowering the operating pressure substantially improved H2 production in an anaerobic, photo-fermentation process.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wang
authors.forename: Siliang
authors.initials: S
authors.lastname: Zhang
authors.forename: Ju
authors.initials: J
authors.lastname: Chu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Huang
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhuang
mesh_terms: D056804:Biofuels / Q000032:analysis*; D001709:Biotechnology / Q000379:methods*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D010313:Partial Pressure; D017440:Photoperiod; D052817:Phototrophic Processes; D012212:Rheology; D012242:Rhodobacter sphaeroides / Q000254:growth & development / Q000378:metabolism*
chemical_list: D056804:Biofuels; D006859:Hydrogen