A. Mickiewicz University, Poznań 60-780 , Poland.
J Appl Microbiol. 2009 Oct;107(4):1308-18. doi: 10.1111/j.1365-2672.2009.04314.x. Epub 2009 Apr 18.
To examine the effects of ammonium ion concentration and illumination intensity on the effectivness of the hydrogen generation process of Rhodobacter sphaeroides.
In all experiments the amount of evolved hydrogen, biomass growth, concentration of ammonium ions, pH and chemical oxygen demand were measured. A nonstructural kinetic model was applied in description of biomass growth, the amount of evolved hydrogen and consumption of organic compounds and ammonium ions. An increase of ammonium ions concentration resulted in a decrease of maximal specific hydrogen potential production. At higher ammonium ion concentrations, no hydrogen evolution was observed. The efficiency of malic acid conversion into hydrogen and the PHB content in the biomass were the highest with lower concentrations of nitrogen compounds.
The presence of ammonium ions inhibits hydrogen photogeneration. A good agreement between the experimental data and model simulations were obtained. In all cases, hydrogen evolution started after an exhaustion of ammonium ions and the increase was proportional to the C/N ratio in the medium. The accumulation of PHB competes with the hydrogen evolution process while the conversion of acids into biomass was limited at higher levels of hydrogen generation.
Confirmation of the suitability of the selected model for kinetic studies of hydrogen photoevolution.
研究铵离子浓度和光照强度对荚膜红假单胞菌产氢效果的影响。
在所有实验中，均测量了氢气的释放量、生物量的增长、铵离子浓度、pH 值和化学需氧量。采用非结构动力学模型来描述生物量的增长、氢气的释放量以及有机化合物和铵离子的消耗。铵离子浓度的增加导致最大比产氢潜力降低。在较高的铵离子浓度下，没有观察到氢气的释放。较低浓度的氮化合物时，苹果酸转化为氢气的效率和生物量中 PHB 的含量最高。
铵离子的存在抑制了氢气的光生成。实验数据与模型模拟之间具有良好的一致性。在所有情况下，当铵离子耗尽后，氢气的释放才开始，并且增加量与培养基中的 C/N 比成正比。PHB 的积累与氢气的产生过程竞争，而在较高的产氢水平下，酸的转化受到限制。
证实所选模型适用于氢气光产生的动力学研究。
