title: Ciprofloxacin toxicity and its co-metabolic removal by a freshwater microalga Chlamydomonas mexicana.
abstract: This study evaluated the toxicity and cellular stresses of ciprofloxacin (CIP) and its co-metabolic removal in a freshwater microalga Chlamydomonas mexicana. The toxicological effects of CIP on C. mexicana were assessed by studying the growth and biochemical characteristics of the microalga including total chlorophyll, carotenoid content, malondialdehyde (MDA) and superoxide dismutase (SOD) activity. The calculated effective concentration (EC50) of CIP on C. mexicana was 65±4mgL-1at 96h. The growth of C. mexicana was significantly inhibited at increased concentrations of CIP, showing 36±1, 75±3. and 88±3% inhibition at 40, 60 and 100mgL-1CIP, respectively, compared to the control after 11days of cultivation. The total chlorophyll, carotenoid, MDA and SOD activity were significantly increased as a result of relatively high concentrations of CIP stress. C. mexicana showed 13±1% removal of CIP (2mgL-1) after 11days of cultivation; however, the addition of an electron donor (sodium acetate, 4gL-1) highly enhanced the removal of CIP (2mgL-1) by>3-fold after 11days. Kinetic studies showed that removal of CIP followed a first-order model (R20.94-0.97) with the apparent rate constants (k) ranging from 0.0121 to 0.079 d-1.
authors.affiliation: Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Jiu-Qiang
authors.initials: JQ
authors.lastname: Xiong
authors.affiliation: Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Mayur B
authors.initials: MB
authors.lastname: Kurade
authors.affiliation: School of Chemical and Biomolecular Engineering, Pusan National University, Busan 609-735, South Korea.
authors.forename: Jung Rae
authors.initials: JR
authors.lastname: Kim
authors.affiliation: Department of Environmental Engineering, Yonsei University, Wonju, Gangwon 220-710, South Korea.
authors.forename: Hyun-Seog
authors.initials: HS
authors.lastname: Roh
authors.affiliation: Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 133-791, South Korea. Electronic address: bhjeon@hanyang.ac.kr.
authors.forename: Byong-Hun
authors.initials: BH
authors.lastname: Jeon
mesh_terms: D001673:Biodegradation, Environmental; D002696:Chlamydomonas / Q000187:drug effects / Q000378:metabolism*; D000460:Chlorophyta / Q000378:metabolism*; D002939:Ciprofloxacin / Q000378:metabolism / Q000633:toxicity*; D004579:Electron Transport; D005618:Fresh Water / Q000737:chemistry*; D007700:Kinetics; D019346:Sodium Acetate / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D019346:Sodium Acetate; D002939:Ciprofloxacin
keywords: Biodegradation; C. mexicana; Ciprofloxacin; Co-metabolism; Emerging contaminant; Redox mediator