Disrupting Calvin cycle phosphoribulokinase activity in Rhodopseudomonas palustris increases the H-2 yield and specific production rate proportionately

作者：McCully Alexandra L; McKinlay James B^*

来源：International Journal of Hydrogen Energy, 2016, 41(7): 4143-4149.

DOI：10.1016/j.ijhydene.2016.01.003

• Hydrogen
• Rhodopseudomonas palustris
• Calvin cycle
• Rubisco
• Phosphoribulokinase

Anoxygenic phototrophs, like Rhodopseudomonas palustris, can convert light energy and electrons from organic waste into H-2 gas, a potential biofuel. During phototrophic growth on organic compounds, the CO2-fixing Calvin cycle competes against H-2 production for electrons. Here we address why genetically disrupting the CO2-fixing enzyme, ribulose 1,5-bisphosphate carboxylase (Rubisco), increases the H-2 yield but not the specific H-2 production rate. We hypothesized that remaining upstream phosphoribulokinase (PRK) activity negatively impacts growth and thereby the specific H-2 production rate, likely due to the accumulation of ribulose-1,5-bisphosphate, the substrate for Rubisco. In agreement with our hypothesis, deletion of PRK resulted in proportional increases to both the H-2 yield and the specific production rate. Thus, even though Rubsico is traditionally a more common target to eliminate Calvin cycle activity we propose PRK as a favorable alternative to avoid undesirable pleiotropic effects.

• 出版日期2016-2-23