Substrate-dependent autoaggregation of Pseudomonas putida CP1 during the degradation of mono-chlorophenols and phenol

Abstract

A bacterium, CP1, identified as Pseudomonas putida strain, was investigated for its ability to grow on and degrade mono-chlorophenols and phenols as sole carbon sources in aerobic shaking batch culture. The organism degraded up to 1.56 mM 2- and 3-chlorophenol, 2.34 mM 4-chlorophenol and 8.5 mM phenol using an ortho-cleavage pathway. P. putida CP1, acclimated to degrade 2-chlorophenol, was capable of 3-chlorocatechol degradation, while P. putida, acclimated to 4-chlorophenol degradation, degraded 4-chlorocatechol. Growth of P. putida CP1 on higher concentrations of the mono-chlorophenols, >or=1.56 mM 4-chlorophenol and >or=0.78 mM 2- and 3-chlorophenol, resulted in decreases in cell biomass despite metabolism of the substrates, and the formation of large aggregates of cells in the culture medium. Increases in cell biomass with no clumping of the cells resulted from growth of P. putida CP1 on phenol or on lower concentrations of mono-chlorophenol. Bacterial adherence to hydrocarbons (BATH) assays showed cells grown on the higher concentrations of mono-chlorophenol to be more hydrophobic than those grown on phenol and lower concentrations of mono-chlorophenol. The results suggested that increased hydrophobicity and autoaggregation of P. putida CP1 were a response to toxicity of the added substrates.

Measurement of the Growth of a Floc Forming Bacterium Pseudomonas putida CP1

“…It was originally isolated from soil in the United States and the identification described elsewhere (Farrell 2000;Farrell and Quilty 2002).…”

“…Pseudomonas putida CP1 formed clumps of cells when grown under certain environmental conditions (Farrell and Quilty 2002). This caused difficulties for monitoring growth.…”

Trophic regulation of autoaggregation in Pseudomonas taiwanensis VLB120

“…In detail, the mutants aggregated on carbon sources like various carbohydrates or gluconate while organic acids like citrate and succinate or utilization of complex media resulted in a planktonic dispersed growth. Carbon source-dependent autoaggregation was so far only reported for P. aeruginosa PAO1 (Klebensberger et al 2006) and Pseudomonas putida (Farrell and Quilty 2002) for which aggregate formation was described upon growth on sodium dodecyl sulfate (SDS) or mono-chlorophenol, respectively. Both studies came to the conclusion that autoaggregation of the strains represented an active response to toxic substrates as a survival strategy in stressful environments.…”

The response of Pseudomonas putida CP1 cells to nutritional, chemical and environmental stresses

“…to and even higher than the concentrations reported for other pollutant-degrading microbes (Farrell & Quilty 2002). The aim of the project is to investigate the response of the organism to nutritional, chemical and environmental stresses at cellular and morphological level.…”