Identification Of Blue Pigment-producing Streptomyces Sp. And Fermentation Condition And Properties Of Blue Pigment

Food security is more concerned with improvement of living level and health protection recognition. Most synthesized pigments have certain harm to health, even produce the cancer-causing effect, so this kind of pigments is limitted to use in many fields. Many researchers have attention to the natural pigments because of having the high security and the certain function. In order to make use of natural pigment produced by microbiology, a blue-pigment producing Streptomyces sp. ZLT was studied extensively in this paper. The results indicated that the blue pigment had higher value.According to analysis of the morphology and physiological & biochemical characteristics, this strain could be identified as Streptomyces coelicolor, named as Streptomyces sp. ZLT.The results indicated that the alkali extraction method was effective. The feasible extraction technical conditions as follows: 0.02mol/LKOH as extraction solvent, for 30min at 50℃, repeating three times and final extraction rate for 96.1%.The blue pigment is water-soluble, dissolves very easily in alkaline solution, ethanol and carbinol, dimethylsulfoxide and N,N-Dimethylformamide etc. The most absorbability wavelength in the range of visible light is 580nm. The blue pigment is relatively stable to temperature, sunlight, most metal ions, VC and acidity agents. It resists UV-ray irradiation and sodium sulfite in alkaline conditions. Oxidize–resistance and reducing–resistance is well at low pH value. Food additives have hyperchromic effect in acidity and alkaline conditions but destroy the pigment in higher pH value. The pigment showed antibacterial only against some gram-positive bacterium. The pigment was nontoxic, could be used in printing & dyeing and foodstuff.The lorthogonal experiment result showed that composition of optimal media was 7% starch soluble, 0.2% KNO₃, 0.075% K₂HPO₄, 0.05% NaCl,0.05% MgSO₄·7H₂O,0.001% FeSO₄·7H₂O. With 10%(V/V) bacterial amount, pH7.5, 35ml loading media, the total pigment relatively value of fermentation broth reached 310 U/ml for 252 hours, which is higher than other reported datum.