Study On Fermentation Of Curdlan

Curdlan is an exopolysaccharide composed entirely ofβ-(1,3)-glucosidic linkages which is produced by bacteria.The unique features of Curdlan,thermic gels and its special molecular structure has attracted the extensive attention of the food industry,light industry, medical and healthcare.In this study,the new mutant strain for Curdlan was induced and its characters for Curdlan fermentation were studied,the ideal culture medium and fermentation condition were investigated.The professes of isolation,purification and separation of Curdlan from fermentation broth were studied.The structure of the purified Curdlan which was separated and purified from fermentation broth was analyzed.The strain Alcaligenes faecalis were treated by UV light,and we find the final mutant U36,which had greatly improved its productivity properties.Through responsive surface we confirm the factors of medium and mathematics of fermentation.When there are 5%glucose, pH6.5,yeast extract 0.5%,KH₂PO₄0.2%,MgSO₄0.05%,afrer 96 hours fermentation at 30℃, the production of curdlan could reach 29g/L,the transformation is 58 percent.The experiment are accordance with responsive surface.Compared with several kinds of extraction method,we think that acid-alkali was fitting to isolation the crude Curdlan.In the further extraction steps,we purify the crude Curdlan by Sevage method,it could descend the content of protein,other metal ions are discard by dialysis.The Curdlan was confirmed a polysaccharide,it was certificated by Congo red test that the absorbtance was same to the standard Curdlan sample.