Analysis of aggregative behavior of Pseudomonas sp. 30-3 isolated from Antarctic soil

Pseudomonas sp. 30-3, a toluene degrading microorganism isolated from oil-contaminated Antarctic soils, was shown to form aggregated flocs of cells when exposed to temperatures of 22 and 4 °C, with an increase in aggregation at 4 °C. This was speculated to be due to the secretion of an extracellular polymeric substance (EPS), thus protecting the organism from cold or frost damage. The flocs of cells were stained with the Live/Dead BacLight Bacterial Viability kit and found to be viable cells. The EPS was identified by lectin binding analysis to consist of N-acetyl-d-glucosamine and N-acetylneuraminic acid. An enzyme-linked lectinosorbent assay was also carried out to quantify the amount of EPS produced at 37, 22 and 4 °C. Results showed that at 37 °C the amount of EPS secreted was low, but there was little difference in the amount of EPS secreted at 22 and 4 °C by Pseudomonas sp. 30-3.