Study On Isolation And Purification, Antioxidation And Antibacterial Activity Of Chlorococcum Sp. GD Polysaccharide

Chlorococcum sp.GD is a low-level prokaryote,rich in polysaccharides,proteins,phenols,?-carotene and other nutrients.It has a wide range of applications in food processing,medical health and other related fields,such as lowering blood sugar and regulating biological immunity.In this thesis,hot water extraction method is used to extract polysaccharides from Chlorococcum sp.GD,and the isolated and purified algal polysaccharides are measured and analyzed to explore their antioxidant and bacteriostatic functions.The main findings are as follows:(1)The DEAE-52 cellulose column was used to chromatographically separate the extracted crude polysaccharides(CCP)of Chlorella vulgaris to obtain three components,which were named CPP-?,CPP-?,and CPP-?.The phenol method was used to determine its percentage content,and the results were found to be 50.80%,25.70%,and 5.43%,respectively;The main component CPP-? was then used to purify it using a Sephadex G-150 gel chromatography column.The component CPP-IV was obtained as a white flocculent,water-soluble acidic polysaccharide.The molecular weight of Chlorococcum sp.GD polysaccharide CPP-IV was determined to be 8090.31 Da.The molar ratio of mannose,rhamnose,galacturonic acid,glucose,galactose,xylose and fucose was 1.68: 3.26: 0.09: 1.00: 4.56: 8.11: 0.28.(2)Chlorococcum sp.GD crude polysaccharide(CCP)and its purified component(CPP-?)have good antioxidant capacity in vitro and strong scavenging ability for various free radicals.The results showed that DPPH had good scavenging ability,and the scavenging ability was similar to that of the positive control Vc at a high concentration,and the IC50 of CPP-IV was0.19 mg·m L-1;The scavenging effect of the two on hydroxyl radicals was similar The clearance rate is 17.6% different from Vc under the highest concentration conditions,and the IC50 of CPP-? is 0.32 mg·m L-1;Overlap phenomenon occurs during the removal of superoxide anion free radicals,andit is consistent at the mass concentration of 0.6 mg·m L-1.The IC50 of CPP-?is 0.97 mg·m L-1;The ability to remove ABTS free radicals and reducing power is not as effective as other free radicals.(3)In addition to Aspergillus niger,CCP and CPP-IV have a significant effect on Proteus species,Acrobacter aerogenes,Staphylococcus aureus,Bacillus subtilis,and Escherichia.coli,Aspergillus flavus,and Monilia albicans all showed some inhibitory effects.And for the same bacteria,the antibacterial effect of CPP-IV was stronger than that of CCP.The study found that compared with the CCP group at a concentration of 30 mg·m L-1,the diameter of the bacterial inhibition zone of CPP-? at the same concentration increased significantly(p ? 0.05).The two bacteria with the strongest CPP-?inhibitory effect were gold.The diameters of staphylococcus aureus and Bacillus subtilis reached 16.57 mm and 16.41 mm,which were significantly higher than the CCP's 11.94 mm and 10.42 mm.