title: Rhamnolipid-enhanced aerobic biodegradation of triclosan (TCS) by indigenous microorganisms in water-sediment systems.
abstract: Bioremediation of triclosan (TCS) is a challenge because of its low bioavailability, persistence in the environment and recalcitrance to remediation efforts. Rhamnolipid (RL) was used to enhance TCS biodegradation by indigenous microbes in an aerobic water-sediment system. However, knowledge of the effects of TCS on the bacterial community and environmental factors in an RL-enhanced, TCS-degrading system are lacking. Therefore, in this study, the influence of environmental factors on RL-enhanced biodegradation of TCS was investigated by single factor experiments, and shifts in aerobic TCS-degrading bacterial populations, with and without RL, were analyzed by high-throughput sequencing technology. The results showed that aerobic biodegradation of TCS was significantly promoted by the addition of RL. Environmental conditions, which included RL addition (0.125-0.5g/L), medium concentrations of TCS (<90μg/g), water disturbance, elevated temperature, ionic strength (0.001-0.1mol/L NaCl) and weak alkaline environments (pH8-9), were monitored. High concentrations of TCS had a remarkable influence on the bacterial community structure, and this influence on the distribution proportion of the main microorganisms was strengthened by RL addition. Alpha-proteobacteria (e.g., Sphingomonadaceae and Caulobacteraceae) might be resistant to TCS or even capable of TCS biodegradation, while Sphingobacteria, Beta- and Delta-proteobacteria were sensitive to TCS toxicity. This research provides ecological information on the degradation efficiency and bacterial community stability in RL-enhanced bioremediation of TCS-polluted aquatic environments.
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: g.qian@mail.scut.edu.cn.
authors.forename: Qian
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: jenniferjiajia@126.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Yan
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, PR China. Electronic address: 1015900630@qq.com.
authors.forename: Junjie
authors.initials: J
authors.lastname: Wen
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, PR China. Electronic address: ppyyhu@scut.edu.cn.
authors.forename: Yongyou
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: 550270345@qq.com.
authors.forename: Yuanbo
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: 1037007852@qq.com.
authors.forename: Wenjin
authors.initials: W
authors.lastname: Wu
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002681:China; D063366:Estuaries; D019015:Geologic Sediments; D006017:Glycolipids / Q000378:metabolism*; D014260:Triclosan / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000891:Anti-Infective Agents, Local; D006017:Glycolipids; D014874:Water Pollutants, Chemical; C418382:rhamnolipid; D014260:Triclosan
keywords: Aquatic environment; Bacterial community structure; Bioavailability; Bioremediation; Biosurfactant; PPCPs