Authors: Miaomiao Liu Yu Zhang Ran Ding Yingxin Gao Min Yang
Publish Date: 2012/11/28
Volume: 97, Issue: 19, Pages: 8805-8812
Abstract
To investigate how the microbial community in activated sludge responded to high antibiotic levels a benchscale aerobic wastewater treatment system was used to treat oxytetracycline OTC mother liquor OTCML Removal efficiency of chemical oxygen demand decreased from 649 to 510 when the OTC level increased from 1916 to 6205 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 OTCML 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 21 × 10−3 in the inoculated sludge to 17 × 10−4–98 × 10−1 in sludge exposed to 6205 mg/L OTC by using realtime PCR The variety of gene cassette arrays of class 1 integron in the sludge samples increased with increasing OTC exposure concentrationThis study was supported by the National Natural Scientific Foundation of China NSFC −51178449 21277162 and State Hitech Research and Development Project of the Ministry of Science and Technology People’s Republic of China 2012AA063401 We greatly thank Mr Huimin Wei and Mr Liren Ren for their kind help in sampling We greatly thank Dr Haifeng Zhang for his assistance in analyzing
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