Scale-up studies for photobiological production of hydrogen

Savaştürk, Dilan.
Photofermentative hydrogen production was performed with sugar sources (glucose, fructose or sucrose) utilized by Rhodobacter capsulatus hupbacteria in both smallscale (indoor) and large-scale (outdoor) reactors. In small-scale experiments, the effect of carbon-to-nitrogen ratio (20, 50 and 80) on photofermentative hydrogen production was investigated with 10, 20 and 30mM glucose and fructose feedings. The highest production rates were obtained from 10 mM glucose and 10 mM fructose as 0.45 mol.m-3 .h-1 and 0.40 mol.m-3 .h-1 , respectively. In the pilot-scale outdoor experiment, stacked tubular photobioreactor (20 L) with manifolds was used. The temperature was maintained around 30°C by a temperature controller. Molasses, side-product of sugar factory, was utilized as a sustainable and renewable feedstock by adjusting to 5 mM sucrose by dilution. The maximum productivity and conversion efficiency were found as 0.52 mol H2.m-3 .h-1 and 54%, respectively. Compared to a previous study of our laboratory, photobioreactor design was improved and scaled-up to 20 L for an economically feasible hydrogen production. The decreased carbon to nitrogen ratio (C/N=13) reduced lag-period for hydrogen production and adaptation period, as observed in small-scale experiments. However, low C/N ratio promoted cell-growth and thus light transmission was limited. Still, maximum productivity was found significantly higher (0.47 mol H2.m-3 .h-1 ) than a similar study with a smaller reactor volume and this indicates that scale-up was successful. To the best of our knowledge, this study is the lowest C/N ratio applied in pilot-scale photofermentative hydrogen production.
Citation Formats
D. Savaştürk, “Scale-up studies for photobiological production of hydrogen,” 2019, Accessed: 00, 2020. [Online]. Available: