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The interest in and demand for natural dyes has increased significantly in recent years; however, very few natural blue dyes are commercially available, because blue colored compounds in nature are relatively rare. In this study, a blue pigment-producing bacteria from Lake Chungará (Atacama Desert, Chile) was isolated, and its blue pigment was purified and chemically characterized. The pigment-producing strain was identified as Pseudarthrobacter sp. by 16S rRNA gene sequencing. The pigment was separated from the filtered culture medium by column chromatography/solid-phase extraction using different resins (ionic exchange, C-18, size exclusion). The strain produced up to 2.5 g L−1 of blue pigment, which was very soluble in water, partially soluble in methanol and insoluble in other organic solvents. The pigment was analyzed and characterized by analytical HPLC, UV–Vis, FT-IR, and H-NMR, and purified by semi-preparative HPLC. The pigment was non-toxic to brine shrimp (LD50 > 2.3 g L−1) and was stable at pH 6–10 at temperatures below 60 °C. HPLC analysis shows that the pigment is composed of four major blue fractions. The physicochemical properties and structural analysis demonstrate that this pigment belongs to the indochrome isomers, whose properties have yet to have been characterized. The high solubility in water, good stability in neutral and basic pH, and negligible toxicity of the blue pigment make it a good candidate suitable for several industrial and possibly some food applications.

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Aims:To analyse the possible effect of poly-b-hydroxyalkanoate (PHA) consumption on 2,4,6-trichloro phenol (2,4,6-TCP) degradation during starvation by Sphingopyxis chilensis S37 strain, which stores PHAs and degrades 2,4,6-TCP. Methods and Results: The strain was inoculated in saline solution supplemented with 2,4,6-TCP (25-400 lM M). Chlorophenol degradation was followed both spectrophotometrically and by chlorine released; viable bacterial counts were also determined. Cells starved for 24, 48 or 72 h were incubated with 25 lM M of 2,4,6-TCP and PHA in cells investigated by spectrofluorimetric and flow cytometry. Results demonstrated that starvation decreased the ability to degrade 2,4,6-TCP. After 72 h of starvation, degradation of 2,4,6-TCP decreased to less than 10% and the relative PHA content diminished to ca 50% during the first 24 h. Conclusion: Utilization of PHA may be an important factor for the degradation of toxic compounds, such as 2,4,6-TCP, in bacterial strains unable to use this toxic compound as carbon and energy source. Significance and Impact of the Study: This is the first study describing a relationship between intracellular PHA consumption and 2,4,6-TCP degradation. Therefore, PHAs provides an endogenous carbon and energy source under starvation and can play a significant role in the degradation of toxic compounds.

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