title: Characterization of cefalexin degradation capabilities of two Pseudomonas strains isolated from activated sludge.
abstract: Pharmaceuticals have recently been regarded as contaminants of emerging concern. To date, there is limited knowledge about antibiotic-degrading microorganisms in conventional activated sludge treatment systems and their characteristics toward antibiotic degradation especially in the presence of a pharmaceutical mixture. As such, antibiotic-degrading microorganisms were investigated and isolated from the activated sludge, and their degradation capabilities were evaluated. Two strains of cefalexin-degrading bacteria CE21 and CE22 were isolated and identified as Pseudomonas sp. in the collected activated sludge. Strain CE22 was able to degrade over 90% of cefalexin, while CE21 was able to remove 46.7% of cefalexin after incubation for 24h. The removal efficiency of cefalexin by CE22, different from that of CE21, was not significantly affected by an increase in cefalexin concentration, even up to 10ppm, however the presence of 1ppm of other pharmaceuticals had a significant effect on the degradation of cefalexin by CE22, but no significant effect on CE21. The degradation product of cefalexin by the two strains was identified to be 2-hydroxy-3-phenyl pyrazine. Our results also indicated that CE21 and CE22 were able to degrade caffeine, salicylic acid and chloramphenicol. Moreover, CE21 was found to be capable of eliminating sulfamethoxazole and naproxen.
authors: State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Medical College, Shantou University, Shantou, Guangdong, China.
authors: Bokun
authors: B
authors: Lin
authors: State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China.
authors: Jinling
authors: J
authors: Lyu
authors: Department of Chemistry, University of Science and Technology of China, Hefei, China; Advanced Laboratory for Environmental Research and Technology (ALERT), USTC-CityU Joint Advanced Research Center, Suzhou, China; Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
authors: Xian-jin
authors: XJ
authors: Lyu
authors: Department of Chemistry, University of Science and Technology of China, Hefei, China; Advanced Laboratory for Environmental Research and Technology (ALERT), USTC-CityU Joint Advanced Research Center, Suzhou, China.
authors: Han-qing
authors: HQ
authors: Yu
authors: Medical College, Shantou University, Shantou, Guangdong, China.
authors: Zhong
authors: Z
authors: Hu
authors: State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China. Electronic address: james.lam@cityu.edu.hk.
authors: James C W
authors: JC
authors: Lam
authors: State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Advanced Laboratory for Environmental Research and Technology (ALERT), USTC-CityU Joint Advanced Research Center, Suzhou, China; Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China. Electronic address: bhpksl@cityu.edu.hk.
authors: Paul K S
authors: PK
authors: Lam
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D002110:Caffeine / Q000378:metabolism; D002506:Cephalexin / Q000378:metabolism*; D002701:Chloramphenicol / Q000378:metabolism; D009288:Naproxen / Q000378:metabolism; D011549:Pseudomonas / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011719:Pyrazines / Q000378:metabolism*; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D020156:Salicylic Acid / Q000378:metabolism; D017423:Sequence Analysis, RNA; D012722:Sewage / Q000382:microbiology; D013420:Sulfamethoxazole / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D011719:Pyrazines; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D014874:Water Pollutants, Chemical; C020364:2-hydroxy-3-phenylpyrazine; D002110:Caffeine; D009288:Naproxen; D002701:Chloramphenicol; D013420:Sulfamethoxazole; D020156:Salicylic Acid; D002506:Cephalexin
keywords: Activated sludge; Biodegradation; Cefalexin; Pharmaceuticals; Pseudomonas