Effects of salinity on the performance, microbial community, and functional proteins in an aerobic granular sludge system

• Published in: Chemosphere (Oxford) Vol. 184; pp. 1241 - 1249
• Main Authors: Wang, Xingang, Yang, Tongyi, Lin, Bing, Tang, Yubin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2017
• Subjects: Aerobic granular sludge; Aerobiosis; Bacteria - drug effects; Functional proteins; Metaproteomic analysis microbial community; Salinity; Salt stress; Sewage - chemistry; Sewage - microbiology; Sodium Chloride - toxicity; Waste Disposal, Fluid - methods; Waste Water; Metaproteomic analysis microbial community; Aerobic granular sludge; Salt stress; Functional proteins
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2017.06.047

The response mechanism of aerobic granular sludge (AGS) systems to salt stress in high-salinity wastewater treatment processes has not been fully elucidated in current studies. The aim of this study was to reveal the comprehensive effects of salinity on AGS characteristics using microbial community and metaproteomics analyses. The results showed that the removal efficiency of COD, TN and TP decreased significantly with increasing salinity. Under salt stress, the Na+ content in AGS decreased, while the K+ and Ca2+ contents increased. This was because the salt-tolerant mechanism of the microorganisms was dependent on the uptake of K+ and ejection of Na+via K+/Na+ pumps, Na+/H+ reversed transport proteins, and K+ channels. Compared with the salt-free condition, 14 of 25 different protein spots were identified successfully by metaproteomic analysis, including porin, periplasmic-binding protein, and ATP-binding cassette-type for phosphonate transporter, which were expressed mainly by members of γ-Proteobacteria and α-Proteobacteria. The variations in functional proteins and microbial community revealed that α- and γ-Proteobacteria had disproportionally active and the metabolic activity of β-Proteobacteria was inhibited by increasing salinity. Additionally, Psychrobacter sp. was confirmed to be a predominant bacterium at 15 g/L NaCl, as the porin was strongly expressed. •Functional proteins in aerobic granule sludge were tested under different salinity.•Reactor performance, granular characteristics and microbial community were monitored.•Psychrobacter sp. was predominant bacteria with plentiful porin expression at high salinity.•The metabolic activity of β-Proteobacteria was inhibited by the increasing salinity.•Porin, periplasmic-binding protein played an important role in high-salt tolerance.