Stability and Antioxidant Activity of Natural Red Pigment by Pseudomonas stutzeri ZH-1

Natural pigments are widely used in textiles, leather, food and other materials, due to they are non-toxic and easy to extract. In the present study, stability and antioxidant activity of a natural red pigment was investigated from Pseudomonas stutzeri ZH-1 which was first isolated and identified from the sludge of Fenhe River, Linfen, Shanxi Province. The results of stability tests showed the red pigment had a relative good stability at pH 5-12 and 30-90°C. The contents of pigments from P. stutzeri ZH-1 were all not significant differences (p>0.05) in a certain concentration of H2O2, Na2S2O8 and NaSO3 at 30 °C for 1h, respectively. In the metal ion solutions being tested for 2h, the pigments retained a residual rate above 80% except for Mg2+ and K+; Additional results of antioxidant activity assays displayed that the nature pigment had the strong scavenging activities against three free radicals including DPPH, ABTS and hydroxyl, and the highest scavenging rates at 0.5 g/L concentrations of pigments were up to 20.58%, 19.23% and 37.69%, respectively. Obviously, the above results suggest the red pigment produced by P. stutzeri ZH-1 which is a promising microbial resources provides a new strategy for the promotion and application of natural pigments.