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Demonstration and optimization of sequential microaerobic dark- and photo-fermentation biohydrogen production by immobilized Rhodobacter capsulatus JP91

Sağır, Emrah, Yucel, Meral, Hallenbeck, Patrick C.
Bioresource technology 2018 v.250 pp. 43-52
Rhodobacter capsulatus, batch systems, biohydrogen, bioreactors, energy, glucose, hydrogen production, inoculum, oxygen, response surface methodology
Hydrogen generation from complex substrates composed of simple sugars has the potential to mitigate future worldwide energy demand. The biohydrogen potential of a sequential microaerobic dark- and photo-fermentative system was investigated using immobilized Rhodobacter capsulatus JP91. Biological hydrogen production from glucose was carried out using a batch process and a bench-scale bioreactor. Response surface methodology with a Box-Behnken design was employed to optimize key parameters such as inoculum concentration, oxygen concentration, and glucose concentration. The maximum hydrogen production (21 ± 0.25 mmol H2/L) and yield (7.8 ± 0.1 mol H2/mol glucose) were obtained at 6 mM glucose, 4.5% oxygen and 62.5 v/v% inoculum concentration, demonstrating the feasibility of enhanced hydrogen production by immobilized R. capsulatus JP91 in a sequential system. This is the first time that a sequential process using an immobilized system has been described. This system also achieved the highest hydrogen yield obtained by an immobilized system so far.