Propachlor Removal by Pseudomonas Strain GCH1 in an Immobilized-Cell System

AUTOR(ES)
FONTE

American Society for Microbiology

RESUMO

A bacterial strain capable of growing on propachlor (2-chloro-N-isopropylacetanilide) was isolated from soil by using enrichment and isolation techniques. The strain isolated, designated GCH1, was classified as a member of the genus Pseudomonas. Washed-cell suspensions of strain GCH1 accumulated N-isopropylacetanilide, acetanilide, acetamide, and catechol. Pseudomonas strain GCH1 grew on propachlor with a generation time of 4.2 h and a rate of substrate utilization of 1.75 ± 0.15 μmol h−1. Gene expression did not require induction but was subject to catabolite expression. Acetanilide was a growth substrate with a yield of 0.56 ± 0.02 mg of protein μmol−1. GCH1 strain cells were immobilized by adsorption onto a ceramic support and were used as biocatalysts in an immobilized cell system. Propachlor elimination reached 98%, with a retention time of 3 h and an initial organic load of 0.5 mM propachlor. The viability of immobilized cells increased 34-fold after 120 days of bioreactor operation.

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