Comparison of single and joint effects of Zn and Cu in continuous flow and batch reactors |
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| Authors: | Sema Sevinç Şengör Petros Gikas James G Moberly Brent M Peyton Timothy R Ginn |
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| Affiliation: | 1. University of California at Davis, Department of Civil and Environmental Engineering, Davis, CA 95616, USA;2. Present Address: Southern Methodist University, Department of Civil and Environmental Engineering, Dallas, TX 75275, USA;3. Present Address: Technical University of Crete, Department of Environmental Engineering, 73100, Chania, Greece, USA;4. Montana State University, Department of Chemical and Biological Engineering, Bozeman, MT 59717‐3920, USA;5. Present Address: Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN 37831, USA |
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| Abstract: | BACKGROUND: Microbial behavior in batch reactors may be different from that in continuous flow reactors, which is expected to affect microbial response to heavy metal exposure. Four parallel continuous flow reactors and batch growth tests were used to investigate the single and joint toxicity of Zn and Cu to Artrobacter sp. JM018. RESULTS: The results indicated that Cu is more toxic than Zn under all conditions. In the batch reactors, all Zn concentrations showed a stimulatory effect on microbial growth. However in the continuous system, 125 µmol L?1 Zn exposure produced inhibition. In the case of mixed Zn and Cu exposures in the batch system, the presence of Zn reduced the severity of Cu inhibition, with a net impact of reduced growth in all cases, whereas in the continuous system microbial growth and substrate utilization rates sharply decreased and ceased. CONCLUSION: The results clearly showed that growth in batch reactors underestimated significantly the heavy metal inhibition, compared with the continuous system. Therefore, the results of batch reactor tests should not be used directly when heavy metal inhibition is to be interpreted for continuous flow systems. Copyright © 2011 Society of Chemical Industry |
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| Keywords: | copper zinc joint toxicity Artrobacter sp. JM018 growth inhibition batch reactor continuous reactor |
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