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Kinetics of atrazine biodegradation by suspended and immobilized mixed microbial cells cultivated in continuous systems
Author(s) -
TafoyaGarnica Angélica,
MacíasFlores Alberto,
RuizOrdaz Nora,
JuárezRamírez Cleotilde,
GalíndezMayer Juvencio
Publication year - 2009
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2121
Subject(s) - atrazine , chemostat , biodegradation , chemistry , biofilm , environmental chemistry , microorganism , bioremediation , degradation (telecommunications) , microbial consortium , bioreactor , bacterial growth , seeding , microbial population biology , environmental engineering , contamination , bacteria , pesticide , environmental science , biology , ecology , agronomy , organic chemistry , telecommunications , genetics , computer science
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