Establishment and characterization of atrazine degrading cultures from Nigerian agricultural soil using traditional and Bio-Sep bead enrichment techniques.
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Date
2011-05
Authors
Omotayo, A.E.
Ilori, M.O
Amund, O.O
Ghosh, D.
Roy, K.
Radosevich, M.
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Abstract
Traditional and in situ enrichment using porous Bio-Sep beads fortified with atrazine were used to
obtain mixed consortia of atrazine-degrading bacteria. Culture derived from both enrichment
techniques showedrapid degradation of atrazine and the composition of consortia varied depending on
enrichment type and atrazine concentration present in both the selective media AND in atrazine
fortified Bio-Sep beads as determined using denaturing gradient gel electrophoresis (DGGE). The
DGGE analysis also revealed the presence of many bands corresponding to various bacteria both
cultured and uncultured. All enrichment cultures possessed trzND genes. The atzBC genes were
detected in all bead enrichments while only atzC was present in one soil enrichment. The atrazine
chlorohydrolase gene (atzA) and Cyanuric acid amidohydrolase genes (atzD) were not detected in any
of the enrichment cultures. In soil samples, trzN and trzD were the only known atrazine catabolic
genes detected. Parallel degradation studies with atrazine potential metabolites showed extensive loss
of these compounds from the culture media. The results indicate that in situ enrichment with Bio-Sep
beads might be a viable method to cultivate atrazine-degrading bacteria not currently represented in
existing culture collections. The triazine chlorohydrolase encoded by trzN commonly found in most
Gram-positive atrazine-degrading bacteria, was more prevalent than atzA. Thus, the detection of
known atrazine-catabolic genes in soil or bacteria from tropical African contaminated system is an
indication of the likely global distribution of these important s-triazine genes.
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Keywords
Atrazine-catabolic genes , S-triazine genes , triazine chlorohydrolase , Denaturing gradient gel electrophoresis , Atrazine chlorohydrolase gene , Cyanuric acid amidohydrolase genes
Citation
Establishment and characterization of atrazine degrading cultures from Nigerian agricultural soil using traditional and Bio-Sep bead enrichment techniques (2011). Applied Soil Ecology 48: 63–70