| Polysaccharides are one of the four basic components of life and are distributed in almost all organisms.Polysaccharides have many biological activities such as anti-oxidation,immune regulation,anti-tumor,lowering blood lipid,etc.,so they have become a hot spot in the research field of low toxicity and high efficiency natural products.Microalgae are not only rich in biological species and have important development and utilization value in food,medicine,chemical industry and other aspects,but also have significant differences in polysaccharide structure and activity with different species and culture conditions,which is an important resource for natural active polysaccharide research.In this paper,the effects of light duration and salt stress on extracellular polysaccharide production in Chlorella protothecoides were investigated.In addition,the exopolysaccharides secreted by chlorella were further purified,their structural characteristics were analyzed,and their biological activities were investigated,which provided a theoretical basis for the development and utilization of exopolysaccharides from chlorella’s main results are as follows:1)In this study,it was found that light cycle and medium salinity had significant effects on the secretion of exopolysaccharide of chloonas.Compared with normal medium salinity and total dark heterotrophic culture conditions,light cycle: darkness was 8 h:16 h,and medium salinity was 10 ‰,the extracellular polysaccharide yield of chloonas increased by 60 %,with a value of 0.297±0.01 g/L.2)After ethanol concentration,Sevag protein removal,DEAE Sepharose Fast Flow anion exchange chromatography and Sephadex G-75 gel filtration chromatography,the homogeneous polysaccharide components CPEPS-A1 and CPEPS-B1 with molecular mass of 131 k DA and 170 k DA were purified.3)Further analysis of the chemical composition of polysaccharides were found CPEPS-A1 and CPEPS-B1 are made of sugar and lipid compounds,including CPEPS-A1 component proportion quality of sugar was 62.66±0.42%,by xylose,mannose and RNA by the mole percentage of 19.81,79.93,0.25,CPEPS-B1 component proportion quality of sugar was 82.58±1.69%,monosaccharide group is divided into rhamnose,glucose,xylose,mannose and its molar percentage was 10.22:46.10:17.98:25.62.Further by using infrared spectrum and nuclear magnetic resonance(NMR)spectroscopy characterization of Chlorella extracellular polysaccharide structure,the results show that CPEPS-A1 and CPEPS-B1 in the components of the polysaccharide structure has beta glycosidic bond configuration,but CPEPS-A1 components by a type of alpha sugar ring and two beta sugar ring monosaccharide composition,CPEPS-B1 components of monosaccharide composition unit contains an alpha type sugar ring and three beta type sugarring.4)Finally,Chlorella extracellular polysaccharide in vitro antioxidant activity and anti-inflammatory activity of the preliminary analysis results show that two kinds of polysaccharide on superoxide anion and DPPH free radical,hydroxyl free radicals and ABTS free radicals are showed strong ability of clear,including CPEPS-A1 component of DPPH free radical,hydroxyl free radicals and ABTS has more strong scavenging free radicals,the half inhibitory concentration were 0.103±0.001,0.362±0.003 and 0.093±0.003 mg/m L;Besides,CPEPS-A1 and CPEPS-B1 components can significantly inhibit lipopolysaccharide(LPS)induced inflammation factor,its anti-inflammatory activity basic and polysaccharide concentrations were positively correlated relationship,including CPEPS-B1 components have a remarkable ability to resist inflammation,when the concentration of effect for 1000 μg/m L,i NOS in mice macrophage RAW 264.7 content as well as the release of ROS,IL-6 and TNF-α levels fell by 48.6%,55.4% and 59.1% respectively.Above results preliminarily explores the light length and salinity stress influence on chlorella extracellular polysaccharide production,select the appropriate light and salinity stress significantly increased the polysaccharide production,at the same time,this study identified chlorella CPEPS-A1 and exopolysaccharide CPEPS-B1 monosaccharide composition,functional groups of components,glycosidic bond and sugar ring configuration,also for two kinds of antioxidant activity of polysaccharide and anti-inflammatory activity carried on the exploration,for the development and utilization of exopolysaccharide chlorella to provide theoretical basis. |
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