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Effect of NaCl on nitrification performance and extracellular polymeric substance characteristic of Klebsiella sp. TN-10

Li, Dan, Jin, Yao, Huang, Jun, Wu, Chongde
Environmental science and pollution research international 2019 v.26 no.24 pp. 24900-24910
Fourier transform infrared spectroscopy, Klebsiella, antioxidant enzymes, catalase, circular dichroism spectroscopy, enzyme activity, nitrification, polymers, polysaccharides, protein secondary structure, proteins, salinity, salt stress, sodium chloride, superoxide dismutase, tanneries, wastewater, zeta potential
Klebsiella sp. TN-10, isolated from tannery wastewater, exhibited excellent nitrification ability cultivated in media with NaCl contents ranging from 0 to 35 g/L. Analysis of antioxidative enzyme activities of TN-10 stressed by NaCl showed that the stain produced more superoxide dismutase (SOD) and catalase (CAT) to fight against salt stress conditions. Moreover, the auto-aggregation index of TN-10 decreased with the increment of NaCl contents, which is consistent with results of zeta potentials. Extinction-emission matrix (EEM) and Fourier-transform infrared (FT-IR) spectrum analyses showed that the compositions of extracellular polymeric substances (EPS) by TN-10 after NaCl shock were similar. Furthermore, proteins and polysaccharides were the main components of EPS, and the contents were greatly influenced by salinity. Then, circular dichroism (CD) spectrum was used to calculate the contents of each protein secondary structure. These results provided further insights into the knowledge of nitrification characteristics, auto-aggregation performance, and EPS compositions of TN-10 during NaCl shock.