Optimization And Application Of Pigment Produced By Rhodotorula

Food pigments involve synthetic and natural pigments.While synthetic pigments are toxic,the study to replace synthetic pigments with natural pigments has drawn more and more attention.As a natural pigment extracted from yeast and other microorganisms,Rhodotorula is a kind of biological active substance with physiological activity,no side effect and high safety.In this paper,two strains of red pigment were obtained from marine silt and yogurt.The strains screened from marine mud were named S bacteria,and the strains selected from yogurt were named Y bacteria.The colony color of S was found to be pink,shape and smooth,and the colony color of Y was pink,shape rule and smooth surface.With microscopical observation,for S,the bacteria are larger,the oval and oval shape of the bacteria can be seen clearly,and the spores are smaller than the bacteria.For Y,the bacteria are larger,the bacteria are large,the oval and oval shape of the bacteria.The size and morphology of the bacteria are uniform and distributed evenly.It is confirmed that both S and Y are yeast.The bacteria producing conditions were optimized by single factor test,and the number of bacteria was measured by blood cell count method.The best conditions for producing bacteria as follows.For S,bacteria temperature is 27,pH value is 4,rocking bed number is 180 rpm/min,carbon source glucose is 2%,nitrogen source ammonium chloride is 1%,metal ion Magnesium Sulfate is 0.8%,and additive citric acid is 0.2%,For Y,bacteria temperature is 24,pH value is 4.The rotary speed is 180 rpm/min,the carbon source glucose is 4%,the nitrogen source ammonium chloride is 1%,the metal ion Magnesium Sulfate is 0.3%,and the additive valine is 0.7%.The conditions of pigment production were optimized by single factor test and spectrophotometric method was used to determine the OD value of pigment production.The best conditions of pigment production as follows.For S,temperature is 24,pH is4,rocking bed number is 180 rpm/min,carbon source glucose is 4%,nitrogen source ammonium sulfate is 1%,metal ion Magnesium Sulfate is 0.5%,and additive valine is 1%.For Y,bacteria temperature is28,pH is 3,shaking table is 180 rpm/min,carbon source glucose is 1%,nitrogen source ammonium chloride is 1.5%,metal ion Magnesium Sulfate is 0.2%,and additive citric acid 0.4%.Under the best culture conditions,the yield of S bacteria was 2.125g/L,while the yield of Y bacteria was 2.000 g/L.The effects of S and Y on the body shape,color and freshness of ornamental carp were studied by contrast experiment.In the basal diet,20 ornamental carps with initial body length of 6 + 0.5cm were fed with the tested feed of S,Y and S mixed bacteria,respectively.The results showed that the experimental group fed with the base feed +S bacteria feed significantly promoted the average body length,the average weight and the fresh brightness of the ornamental carp,and the ratio of the best base feed to the S bacteria was 98.5% base feed +1.5%S bacteria.Rhodotorula is used as a probiotic in the feed of ornamental birds and aquatic animals to improve the growth,growth vitality and bright skin.And it can also be applied in many fields,such as food addition,textile,clothing dyeing and so on.