caa a22 4500 605504407 CHVBK 20210128100616.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s00253-014-6161-1 doi (NATIONALLICENCE)springer-10.1007/s00253-014-6161-1 Intracellular azo decolorization is coupled with aerobic respiration by a Klebsiella oxytoca strain [Elektronische Daten] [Lei Yu, Xiao-yu Zhang, Tian Xie, Jin-mei Hu, Shi Wang, Wen-wei Li] Reduction of azo dye methyl red coupled with aerobic respiration by growing cultures of Klebsiella oxytoca GS-4-08 was investigated. In liquid media containing dye and 0.6% glucose in a mineral salts base, 100mgl−1 of the dye are completely removed in 3h under shaking conditions. The dye cannot be aerobically decolorized by strain GS-4-08 without extra carbon sources, indicating a co-metabolism process. Higher initial dye concentration prolonged the lag phase of the cell growth, but final cell concentrations of each batches reached a same level with range from 6.3 to 7.6mgl−1 after the dye adaption period. This strain showed stronger dye tolerance and decolorization ability than many reported strains. Furthermore, a new intracellular oxygen-insensitive azoreductase was isolated from this strain, and the specific activity of enzyme was 0.846 and 0.633Umg−1 protein in the presence of NADH and NADPH, respectively. N,N dimethyl-p-phenylenediamine and anthranilic acid were stoichiometrically released from MR dye, indicating the breakage of azo bonds accounts for the intracellular decolorization. Combining the characteristics of azoreductase, the stoichiometry of EMP, and TCA cycle, the electron transfer chain theory of aerobic respiration, and the possible mechanism of aerobic respiration coupled with azo reduction by K. oxytoca GS-4-08 are proposed. This study is expected to provide a sound theoretical basis for the development of the K. oxytoca strain in aerobic process for azo dye containing wastewaters. Springer-Verlag Berlin Heidelberg, 2014 Azoreductase nationallicence Aerobic respiration nationallicence Azo reduction nationallicence Klebsiella oxytoca nationallicence Yu Lei Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut Zhang Xiao-yu Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut Xie Tian Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut Hu Jin-mei Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut Wang Shi Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut Li Wen-wei Department of Chemistry, University of Science and Technology of China, 230026, Hefei, China aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/5(2015-03-01), 2431-2439 0175-7598 99:5<2431 2015 99 253 https://doi.org/10.1007/s00253-014-6161-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-014-6161-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yu Lei Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut NATIONALLICENCE 700 1- Zhang Xiao-yu Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut NATIONALLICENCE 700 1- Xie Tian Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut NATIONALLICENCE 700 1- Hu Jin-mei Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut NATIONALLICENCE 700 1- Wang Shi Department of Environmental Engineering, Nanjing Forestry University, 210037, Nanjing, China aut NATIONALLICENCE 700 1- Li Wen-wei Department of Chemistry, University of Science and Technology of China, 230026, Hefei, China aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/5(2015-03-01), 2431-2439 0175-7598 99:5<2431 2015 99 253