Kars, GokhanCeylan, Ayca2020-03-262020-03-2620130360-31991879-3487https://dx.doi.org/10.1016/j.ijhydene.2013.03.013https://hdl.handle.net/20.500.12395/29267The production of biohydrogen and 5-aminolevulinic acid (5-ALA) by Rhodobacter sphaeroides O.U.001 was investigated in a biorefinery concept. Waste barley was used as a substrate after acid hydrolysis. The hydrolysate was analyzed in terms of its total simple sugar, organic acid, ammonium, element and total phenol contents. Four different growth media having 5 g/L, 7 g/L, 9 g/L and 11 g/L sugar content were prepared using the waste barley hydrolysate to produce biohydrogen and 5-ALA. The increased sugar concentrations resulted in higher cell density and hydrogen accumulation. Accordingly, the highest cell density (OD660: 1.78) and hydrogen production (0.4 L H-2/L culture) were observed in the 11 g/L sugar-containing medium. A 67.4 mu M 5-ALA was produced upon vitamin B-12 and levulinic acid additions. These results showed that waste barley can be used as a substrate for R. sphaeroides for biohydrogen and 5-ALA production within a biorefinery concept. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.en10.1016/j.ijhydene.2013.03.013info:eu-repo/semantics/closedAccessBiohydrogenAminolevulinic acidRhodobacter sphaeroidesWaste barleyBiorefinery conceptArticle381455735579Q1WOS:000319232500009Q2