title: Effects of Cu exposure on enzyme activities and selection for microbial tolerances during swine-manure composting.
abstract: A simulated experiment of aerobic composting was conducted on swine manure to evaluate the effects of Cu at two exposure levels (200 and 2000 mg kg(-1), corresponding to low-Cu and high-Cu treatments, respectively) on the activity of microorganisms. In addition, the microbial pollution-induced community tolerance (PICT) to Cu and co-tolerance to selected antibiotics (tylosin and vancomycin) in the composted products were also investigated using the Biolog Ecoplates™ method. It was demonstrated that the enzymatic activities were significantly inhibited by the high-Cu treatment, with maximal inhibition rates of 56.8% and 65.1% for urease and dehydrogenase, respectively. In response to the PICT test, the IC50 (half-maximal inhibition concentrations) values on the microorganisms in the high-Cu-treated composts were clearly higher than those in the low-Cu-treated and control composts, for the toxicity tests on both Cu and antibiotics, including tylosin and vancomycin. The data demonstrated that high-Cu exposure to the microbial community during the composting not only selected for Cu resistance but also co-selected for antibiotic resistance, which was of significance because the tolerance might be transferred to the soil after the land application of composted manure.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 100875 Beijing, China. Electronic address: liyxbnu@bnu.edu.cn.
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 100875 Beijing, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 100875 Beijing, China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 100875 Beijing, China.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, 100875 Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000201:enzymology; D003300:Copper / Q000032:analysis*; D024881:Drug Resistance, Bacterial; D008372:Manure; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D012037:Refuse Disposal; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D013552:Swine; D015645:Tylosin / Q000737:chemistry; D014510:Urease / Q000037:antagonists & inhibitors*; D014640:Vancomycin / Q000737:chemistry; D019155:Veterinary Drugs / Q000737:chemistry
chemical_list: D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D019155:Veterinary Drugs; D014640:Vancomycin; D003300:Copper; D010088:Oxidoreductases; D014510:Urease; D015645:Tylosin
keywords: Composting; Cu; Enzyme activity; Microorganisms; Pollution-induced community tolerance (PICT)