title: Response of activated sludge to the treatment of oxytetracycline production waste stream.
abstract: To investigate how the microbial community in activated sludge responded to high antibiotic levels, a bench-scale aerobic wastewater treatment system was used to treat oxytetracycline (OTC) mother liquor (OTC-ML). Removal efficiency of chemical oxygen demand decreased from 64.9 to 51.0 % when the OTC level increased from 191.6 to 620.5 mg/L, respectively. According to the cloning results, Psychrobacter and Cryptophyta were the dominant bacterium and eukaryote in the inoculated sludge, respectively, both of which related to low temperature. After OTC exposure, Alphaproteobacteria and Betaproteobacteria became the dominant bacteria, with a small proportion of Firmicutes, Actinobacteria appeared, and fungi (mainly Saccharomycotina) became the dominant eukaryotes, indicating the possible functions of these microorganisms in the wastewater treatment of OTC-ML. The relative abundance of nine tetracycline resistance genes and four mobile elements (class 1 integron, class 2 integron, transposon Tn916/1545, and pattern 1 insertion sequence common region) significantly increased from undetectable to 2.1 × 10(-3) in the inoculated sludge to 1.7 × 10(-4)-9.8 × 10(-1) in sludge exposed to 620.5 mg/L OTC by using real-time PCR. The variety of gene cassette arrays of class 1 integron in the sludge samples increased with increasing OTC exposure concentration.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085, China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ran
authors.initials: R
authors.lastname: Ding
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Gao
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D058448:Biota; D024881:Drug Resistance, Bacterial; D056890:Eukaryota / Q000254:growth & development; D020071:Interspersed Repetitive Sequences; D054892:Metagenome; D008969:Molecular Sequence Data; D010118:Oxytetracycline / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D010118:Oxytetracycline; D012722:Sewage; D062065:Wastewater