A kinetic study of hydrogen production by a Calvin-Benson-Bassham cycle mutant, PRK (phosphoribulose kinase), of the photosynthetic bacterium Rhodobacter capsulatus

作者：Liu Yuan; Hallenbeck Patrick C^*

来源：International Journal of Hydrogen Energy, 2016, 41(26): 11081-11089.

DOI：10.1016/j.ijhydene.2016.03.203

• Rhodobacter capsulatus JP91
• Phosphoribulose kinase mutant
• Single stage photofermentation
• H-2 yield and productivity
• Electron allocation analysis
• Bacterial chlorophyll

In the purple non-sulfur photosynthetic bacteria, the Calvin-Benson-Bassham (CBB) cycle plays a role in maintaining intracellular redox balance under photoheterotrophic growth conditions, potentially consuming reductant and chemical input (ATP) that could be used for H-2 production by nitrogenase. Previous studies have shown Rhodobacter capsulatus JP91 to be a remarkable H-2 producer and in the present study a PRK, phosphoribulose kinase, knockout mutant of this strain was created in an attempt to further improve H-2 yield. Analysis of growth with different carbon sources showed that this mutant could only grow in acetate medium without, however, producing any H-2. A spontaneous mutant was recovered which had gained the ability to grow on glucose and produce H-2 with a yield that was 20-40% greater than the wild type, JP91 strain. Analysis shows that growth and hydrogen production are strongly linked with electrons from glucose mostly directed to H-2 production and biomass formation.