Pyocyanin is a blue green phenazine pigment produced in large quantities by active cultures ofPseudomonas aeruginosa, with advantageous applications in medicine, agriculture and for the environment. Hence, in the present study, a potent bacterium was isolated from agricultural soil and was identified morphologically and by 16S rRNA sequencing as P. aeruginosa (isolate KU_BIO2). When the influence of nutrient supplements in both King's A and Nutrient media as amended was investigated, an enhanced pyocyanin production of 2.56 µg ml −1 was achieved in King's A medium amended with soya bean followed by 1.702 µg ml −1 of pyocyanin from the nutrient medium amended with sweet potato. Purified pyocyanin was characterized by UV-Vis Spectrophotometer and Fourier-Transform Infrared spectroscopy (FTIR). Furthermore, Liquid Chromatography Mass Spectrum (LCMS) and Nuclear Magnetic Resonance (NMR) confirmed its mass value at 211 and as N-CH 3 protons resonating at 3.363 ppm as a singlet respectively. The isolated pyocyanin displayed remarkable dye property by inducing color change in cotton cloth from white to pink. Lastly, the antifungal activity of test pyocyanin showed inhibition of growth of rice blast fungus, Magnaporthe grisea and bacterial blight of rice, Xanthomonas oryzae at concentrations of 150 and 200 ppm, respectively. Thus, this investigation provides evidence for diverse actions of pyocyanin which are nutrient dependent and are capable of acting on a large scale, by utilizing microbes existing in agriculture wastes, and thus could be used as an alternative source in the making of natural textile dyes with strong durability and a broad spectrum of ecofriendly agrochemicals.Microorganisms are biological agents which help to solve many problems related to health, agriculture and the environment 1-3 . Microorganisms have been the study at interest in recent years because of production of novel secondary metabolites 4 . These metabolites exhibit antimicrobial, antiviral or antitumor as well as anticoagulant properties, and the production of secondary metabolites may have evolved as an alternative strategy to switching off metabolic pathways by various control mechanisms 5-7 . Products of secondary metabolism, such as pigments, could also be of considerable selective advantage since they could eliminate possible microbial competitors 8 .Natural pigments have been obtained and used since long ago, but interest in them has decreased due to toxicity problems. Hence, pigments from microbial sources are good alternatives for various applications 9,10 . Pseudomonas aeruginosa is one of the most commercially valuable organisms, many of which are responsible for producing soluble pigments like pyocyanin (blue), pyoveridin (yellow-green), pyorubin (red) and pyomelanin (brown) 11 . P. aeruginosa produces pyocyanin (N-methyl-1-hydroxyphenazine) which is a water soluble

In the present study, antibiotic residues were detected in milk samples collected from the dairy herds located in Karnataka, India, by microbiological assay. Subsequently, the detected antibiotics were identified as azithromycin and tetracycline, by high-performance liquid chromatography, further both the antibiotics detected in the cow milk samples were found to be at high concentration (9708.7 and 5460 μg kg-1, respectively). We then investigated the effects of temperature and pH on the stabilities of azithromycin and tetracycline to determine the degradation rate constant k using first-order kinetic equation. Results indicated that significant reduction in stability and antibacterial activity of azithromycin solution when subjected to 70 and 100°C for 24 h. While stability of tetracycline was significantly reduced when subjected to 70 and 100°C for 24 h. However no significant reduction in antibacterial activity of tetracycline was observed at respective temperatures when compared with that of control. In addition, the stabilities of azithromycin and tetracycline were found to be decreased in acidic pH 4–5. The results of the present study revealed the high risk of contamination of milk sample with veterinary antibiotics and also demonstrated the effect of temperature and pH on stability of antibiotics. Therefore the study suggest that the qualitative and quantitative screening of milk for the presence of antibiotics need to be strictly performed to ensure safe drinking milk for consumers.

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