Characterization of extracellular polymeric substances from biofilm in the process of starting-up a partial nitrification process under salt stress.
In this study, the characteristics of extracellular polymeric substance (EPS) fractions of biofilm during the process of establishing a partial nitrification under salt stress were analyzed in terms of concentrations, molecular weight distribution, and three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy. A partial nitrification was formed successfully with a salinity of 1%. Results indicated that the amount of total EPS increased from 54.2 mg g⁻¹ VSS⁻¹ on day 1 to 99.6 mg g⁻¹ VSS⁻¹ on day 55 due to the NaCl concentration changed from 0 to 10.0 g L⁻¹ in a biofilm reactor. The changes of loosely bound EPS (LB-EPS) compounds under different salt concentrations appeared to be more significant than those of the tightly bound EPS. A clear release of polysaccharides in the LB-EPS fraction was detected during the enhancement of salinity. This was considered as a protective response of bacteria to the salinity. Three fluorescence peaks were identified in the EEM fluorescence spectra of the EPS fraction samples. Two peaks were assigned to the protein-like fluorophores, and the third peak was located at the excitation/emission wavelengths of 275 nm/425-435 nm of the spectra of EPS fractions till the salinity maintained constant at 1%. This information is valuable for understanding the characteristics of EPS isolated from biomass in a saline nitrogen removal system.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China.
Zhao-Ji
ZJ
Zhang
Shao-Hua
SH
Chen
Shu-Mei
SM
Wang
Hong-Yuan
HY
Luo
D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D018441:Biofilms; D008970:Molecular Weight; D058465:Nitrification; D011108:Polymers / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification; D011135:Polysaccharides, Bacterial / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D012492:Salts / Q000633:toxicity*; D013050:Spectrometry, Fluorescence; D013312:Stress, Physiological
D001426:Bacterial Proteins; D011108:Polymers; D011135:Polysaccharides, Bacterial; D012492:Salts