Kinetics of atrazine biodegradation by suspended and immobilized mixed microbial cells cultivated in continuous systems
✍ Scribed by Angélica Tafoya-Garnica; Alberto Macías-Flores; Nora Ruiz-Ordaz; Cleotilde Juárez-Ramírez; Juvencio Galíndez-Mayer
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2009
- Tongue
- English
- Weight
- 225 KB
- Volume
- 84
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
Abstract
BACKGROUND: Using a suspended or immobilized microbial community obtained through chemostat selection from agricultural soils formerly treated with triazinic herbicides, the atrazine biodegradation kinetics in continuous aerobic reaction systems was studied.
RESULTS: When microbial cells were continuously cultivated on atrazine as the sole nitrogen and carbon source, atrazine removal efficiencies η~ATZ~ near to 100% were reached, although accumulation of metabolic byproducts was detected. The fluidized‐bed biofilm reactor allowed atrazine removal rates R~V, ATZ~ higher than that permitted by suspended cell cultures with similar removal efficiencies. In this system, the highest volumetric removal rate was obtained (R~V, ATZ~ = 12.2 mg L^−1^ h^−1^), with herbicide removal efficiencies η~ATZ~ near 100% and reduced accumulation of byproducts.
CONCLUSIONS: With the operational conditions probed in continuous suspended‐cell culture, increasing the C:N ratio in the inflowing medium resulted in higher cell growth yields but not in better atrazine removal rates. Kinetic results showed that for similar working conditions higher R~V, ATZ~ values and reduced amounts of degradation byproducts of recalcitrant organic compounds could be expected with multi‐stage biofilm reactors. Copyright © 2009 Society of Chemical Industry