Starvation survival of Gordonia polyisoprenivorans CCT 7137, isolated from contaminated groundwater in Brazil

Gordonia polyisoprenivorans CCT7137, exopolysaccharide-producing bacterium, was isolated from groundwater contaminated with leachate in a former municipal landfill site (Sao Paulo, Brazil). The strain was submitted to starvation in phosphate-buffered saline solution for 56 days so as to evaluate its behavior regarding cuturability and cell morphology. As a response to starvation, G. polyisoprenivorans CCT7137 presented reduction in viable cell count, cell size and cell shape alteration. The initial number of viable cells was 1.51 × 107 c.f.u. ml. After 7 days of starvation culturability dropped to 13.70% (2.07 × 106 c.f.u/ml) and, after 56 days, to 3.25% (4.93 × 105 c.f.u/ml). It was also observed that after 7 days of starvation the cell size presented an average reduction in the values of length, length/width ratio, volume and area of 50, 58, 40 and 42%, respectively. The length/width ratio showed a change of shape from rod to coccobacillus. Changes in cell dimensions and distribution of cell into classes were not significant after day 7 of starvation. The results obtained show that it is not necessary for the strain to starve for more than a week to obtain G. polyisoprenivorans CCT7137 size- reduced cells. The results also indicate the potential for its starved forms to be used in future tests in porous medium to study the production of exopolysaccharide in situ.