Identification Of Actinomycetes Producing Blue Pigment And Optimization Of Pigment Extraction Conditionsand And Nature Research

In order to obtain a safe,stable blue pigment and high blue pigment producing strain,a blue streptococci strain was isolated from chayote,and the strain was identified and liquid fermented.Blue acid was obtained by acid-base extraction.The study of the properties of blue pigments,optimization of the fermentation conditions of streptomycetes and the extraction method of blue pigments were carried out to verify the feasibility of blue pigments for food additives,and to verify whether the strain can produce safe and stable blue pigments with high yield.The main contents are as follows:1.Isolation and identification of strain.A strain of streptomyces sp.FSG-003 was screened from chayote,and identified from three aspects: morphological characteristics,physiological and biochemical characteristics,and molecular biological of strain.Its morphological characteristics,physiological and biochemical characteristics are very close to streptomycetes cyanosis,phylogenetic analysis based on the 16 S rDNA series,streptomycetes FSG-003 is in the same branch with Streptomyces sp.strain SN0280,and has a close relationship with the parent.2.Fermentation of the streptomycetes FSG-003,extraction of blue pigment and method optimization.The optimized fermentation conditions after response surface optimization were as follows: sweet potato starch as carbon source,peanut meal as nitrogen source,initial pH of medium was adjusted to 7,inoculation volume was 20%,bottling volume was 37%,and rotation speed was 150 r/min,fermentation temperature was 23?,and fermentation was performed for 9 d.The optimized best extraction conditions through single factor test: the fermentation broth pH was 12,and centrifuged at 8000 r/min for 15 min at 4?.Remove sediment from supernatant and the supernatant pH is 1,4?,10000 r/min centrifugal for 15 min,optimized yield of blue pigment up to 11.3 g/L.3.Preliminary isolation,identification and properties of blue pigments.The maximum absorption wavelength of blue pigment measured by ultraviolet spectrophotometer is 291 nm;Preliminarily separated and identified by HPLC showed that more than 7 substances were expected to be present in crude extract of blue pigment;Explore the influence of various factors on the stability of blue pigment;After an acute toxicity test,it is known that blue pigment is basically nontoxic;The blue pigment crude extract contains no Te and Cd,the content of Pb is also very low,and the content of Zn is high;Blue pigment has antibacterial activity against all eight tested bacteria,the higher the blue pigment concentration,the more obvious the inhibitory effect.