Fig. 1

Transmission electron micrographs (a and b) and extracellular pigment production (c) of Methylibium sp. T29. For TEM examination the cells were suspended in 18 MΩ ultra-pure water, and 10 μl of the cell suspension was placed on carbon- and Formvar-coated 300 Mesh copper grids. Single 10 μl drops of 1 % (w/v) aqueous uranyl acetate were added to the grid for 15 s. The images were taken on a Hitachi S-4800 type (FEG) scanning electron microscope in transmission mode using 25 kV acceleration voltage. Scale bars represent 1 μm. The morphology of the cells is similar to M. petroleiphilum PM1’s [6]. While grown on ½ × TSA plates M. sp. T29 secreted a brownish pigment resembling pyomelanin produced by certain Pseudomonas spp