title: Simultaneous Decolorization and Biohydrogen Production from Xylose by Klebsiella oxytoca GS-4-08 in the Presence of Azo Dyes with Sulfonate and Carboxyl Groups.
abstract: Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture ofKlebsiella oxytocaGS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter-1of xylose as the substrate, a maximum xylose utilization rate (URxyl) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H2mol of xylose-1, respectively, were obtained. Biohydrogen kinetics and electron equivalent (e-equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes.IMPORTANCEThe pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such as lignin, whose reclamation is considered economically crucial and environmentally friendly. Furthermore, azo dyes are usually added in order to fabricate anticounterfeiting paper, which further increases the complexity of the pulp and paper wastewater. This work may offer a better understanding of biohydrogen production from xylose in the presence of azo dyes and provide a promising energy-recycling method for treating pulp and paper wastewater, especially for those containing azo dyes.
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China lyu@njfu.edu.cn xsong@issas.ac.cn.|Jiangsu Key Laboratory of Biomass Energy and Materials, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing, China.
authors.forename: Lei
authors.identifier: http://orcid.org/0000-0003-3975-8903
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Ming-Yue
authors.initials: MY
authors.lastname: Cao
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Peng-Tao
authors.initials: PT
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Ying-Rong
authors.initials: YR
authors.lastname: Yue
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Wen-Duo
authors.initials: WD
authors.lastname: Yuan
authors.affiliation: Department of Environmental Engineering, Nanjing Forestry University, Nanjing, China.
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Qiao
authors.affiliation: Jiangsu Key Laboratory of Biomass-Based Green Fuels and Chemicals, Nanjing, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, China lyu@njfu.edu.cn xsong@issas.ac.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Song
mesh_terms: D000476:Alkanesulfonates / Q000378:metabolism; D001391:Azo Compounds / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D007700:Kinetics; D041121:Klebsiella oxytoca / Q000235:genetics / Q000378:metabolism*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D014994:Xylose / Q000378:metabolism*
chemical_list: D000476:Alkanesulfonates; D001391:Azo Compounds; D004396:Coloring Agents; D006859:Hydrogen; D062065:Wastewater; D014994:Xylose
keywords: Klebsiella oxytoca; biohydrogen production; decolorization; xylose