Applications Of Extracellular Polysaccharide Produced By Marine Bacterium Polaribacter Sp. SM1127

There is 71%of the ocean's area in the earth,and the vast ocean is home to a varnety of microorganisms.Even in extreme marine environments,there are many microorganisms.The ocean covers 71%surface area of the earth.In seawater,there are many kinds of microorganisms,and the distribution is also extensive.Even in extreme habitats,there are many microorganisms.The Arctic Gulf is characterized by low temperature,high salinity,and significant seasonal variations.Some extreme microorganisms such as thermophiles,halophiles,and pressure-resistant bacteria exhibit different characteristics and can provide special functional gene sources.Therefore,marine extreme microorganisms are of great application value.The extracellular polysaccharide of microorganisms is a kind of carbohydrate polymer with high molecular weight,which not only plays an important role for microorganisms in resisting harsh environments,but also has wide application value in food,medicine and other fields.In this paper,the marine bacterium Polaribacter sp.SM1127,isolated from the intertidal zones of Kongsfjorden,was used to study the effects of various inorganic salt ions on the yield of extracellular polysaccharides under artificial seawater conditions.Moreover,the application potential of the extracellular polysaccharide was evaluated.The results indicate that the exopolysaccharide of Polaribacter sp.SMI 127 has great research value and broad application prospects.1.Effects of inorganic salt components on the extracellular polysaccharide production of Polaribacter sp.SM1127High concentration of Cl-tends to cause more serious corrosion effects on stainless steel fermentation equipment.It is reported that other inorganic salt components also have certain negative effects.On this basis,the effects of reducing the concentration of Cl-and removing other inorganic salt components on the extracellular polysaccharide production of strain SM1127 were explored.First,the concentration of NaCl in artificial seawater was reduced from 26.7 g/L to 1 g/L,2 g/L,3 g/L,4 g/L and 5 g/L.It was found that the yield of extracellular polysaccharide was highest at 4 g/L NaCl.Then,the yield of extracellular polysaccharide was analyzed when single inorganic salt component in artificial seawater was removed.It was found that when MgCl2,MgSO4 and CaCl2 were removed respectively,the yield of extracellular polysaccharide was decreased significantly.And the effect of CaCl2 was the most significant.When Al2Cl6,H3BO3,Na2SiO3,NH3 · H2O and LiNO3 were removed respectively,the production of extracellular polysaccharide was decreased lightly.The yield of extracellular polysaccharides was also analyed when several inorganic salt components in artificial seawater were removed together.When AICl3,H3BO3,Na2SiO3 and LiNO3 were removed,the yield of extracellular polysaccharide was decreased by 21%.However,when MgCl2,MgSO4 and CaCl2 were removed,the yield of extracellular polysaccharide was reduced by 80%.When the content of several inorganic salt components such as MgCl2,MgSO4,and CaCl2 was reduced to a half,the yield of extracellular polysaccharide was decreased by 32%.It can be seen that MgCl2,MgSO4 and CaCl2 were the main inorganic salt components affecting the extracellular polysaccharide yield of strain SM1127.2.Cryoprotective effect of bacterial SM1127 exopolysaccharide in ecologyThe ecological function of bacterial extracellular polysaccharides was closely related to its surrounding natural environment.Studies had shown that in the case of extracellular polysaccharide coating,bacterium grows better than bacterium without extracellular polysaccharide coating.In this study,the cryoprotective effect of exopolysaccharide secreted by strain SM1127 on strain SM1127 and Escherichia coli DH5a were studied.The addition of extracellular polysaccharide can significantly increase the survival cell number of strain SM1127 and E.coli DH5a was increased.With the increase of extracellular polysaccharide concentration,the survival cell number of strain SM1127 was significantly increased.When the extracellular polysaccharide concentration was 20 mg/mL,the survival cell number of strain SM1127 reached the most,4.3 X 106/mL.which was 3 times of that of the control without extracellular polysaccharide.With the increase of extracellular polysaccharide concentration,the survival cell number of E.coli DH5a was also significantly increased.When the extracellular polysaccharide concentration was 20 mg/mL,the survival cell number of E.coli DH5? reached the most,5.2x107/mL,which was 10 times of that of the control without extracellular polysaccharide.Therefore,the extracellular polysaccharide produced by strain SM1127 has good cryoprotective effect in natural ecological environment and may have potential in strain cryopreservation.3.Application potentials of Polaribacter sp.SM1127 extracellular polysaccharideUnder UVB-exposure,the strain SM1127 extracellular polysaccharide could increase the survival rate of human dermal fibroblasts.As the concentration of extracellular polysaccharide increased,the concentration of lactate dehydrogenase was gradually decreased.The lower concentration of exopolysaccharide(0.5 mg/mL)was not effective in reducing the concentration of reactive oxygen species.When the concentration of extracellular polysaccharide was 4 mg/mL,the concentration of reactive oxygen species could be reduced under UVB irradiation.The concentration of GSH was increased as the concentration of exopolysaccharide increased.When the concentration of extracellular polysaccharide was 4.0 mg/mL,the concentration of GSH was increased to 13 ?mol/gprot.In addition,UVB irradiation can significantly reduce the enzyme activity of SOD.When the concentration of extracellular polysaccharide was 4.0 mg/mL,the enzyme activity of SOD in the cell was almost the same as that of the control.UVB irradiation has a great influence on the activity and morphology of the cells.The addition of different concentrations of extracellular polysaccharides could protect cells.In the rat skin wound test,the application of extracellular polysaccharide on the wound promoted the repair of the wound,and the effect of the high concentration of extracellular polysaccharide was more obvious.After 16 days,the wound was healed by applying 5 mg of extracellular polysaccharide daily.In addition,in the frostbite test,the experimental group of the extracellular polysaccharide was healed a little faster than the untreated group,the edema was relieved at 14 days,the dermis and subcutaneous tissues were repaired,and the fibroblasts were increased.The presence of extracellular polysaccharides can reduce frostbite on the skin at low temperature.Therefore,the extracellular polysaccharide produced by strain SM1127 can help HDF resist UV radiation damage,promote the healing of skin wound,and reduce the damage of skin caused by low temperature.It has a good application potential in the fields of medicine and cosmetics..