Culture, Polysaccharide Extraction And RAPD Analysis Of Three Species Porphyridium

The unicellular red alga Porphyridium is abundant of useful bioactive materials such as polysaccharide, polyunsaturated fatty acids (AA and EPA) and phycobiliproteins. Therefore, Porphyridium has broad utilization prospects for pharmaceutical and chemical industry. The overseas studies on it have been reported since 1960, but few researches have been carried out in china. In this paper, the culture condition, polysaccharide extraction and RAPD analysis of three species of Porphyridium were studied.Porphyridium is one of the most important primal productivity in the sea, and large-scale cultivation is the most important problem in the exploitation of microalgae. In order to optimize the culture conditions of Porphyridium, The influences of different conditions on cells density, such as different intensity, different photoperiod, different culture methods and different components of cultural medium were investigated. The results showed that the suitable conditions of Porphyridium aerugineum 755 are light intensity 2500Lx, photoperiod 14L:10D, salinity 1%, NaHCO3 400mg/L, glucose 1%, shaken better than static culture. The suitable condition of Porphyridium purpureum 806 are light intensity 2500Lx, photoperiod 18L:6D, salinity 3%, NaHCO31200mg/L, shaken better than static culture. The suitable condition of Porphyridium cruentum are light intensity 1500Lx, photoperiod 24L:0D, salinity 3%, NaHCO3 1200mg/L, shaken better than static culture.The red microalga Porphyridium was a source of many natural products, expecially sulphurized polysaccharide which causes the culture to become viscous. The expolysaccharids (EPS) was high-molecular weight polymers with complex chemical structure, which used commercial application in a variety of fields including the paper and textile, food, cosmetics, and chemical and pharmaceutical industries. But the most impressive was its antiviral activity against many virus.This paper reports that the optimum extraction of exopolysaccharides process by orthogonal design and the effect of different carbonic(C) and nitrogen(N) sources on cellgrowth rate and exopolysaccharides production of three Porphyridiums. The optimum extraction process was selected with the L9(34) orthogonal design. The significant effects of alcohol concentration, alcohol volume and percolation time on the extraction of expolysaccharids, were discovered. Certain amount of proteins were contained in the crude polysaccharide extracting from Porphyridium. Deproteinized from crude polysaccharide by adopting Sevag method.Through orthogonal test, we found that the best constitution for extracting polysaccharide from Porphyridium aerugineum 755 were as follow: alcohol concentration was 50%, alcohol volume was 3-fold time , percolation time was 1.5h , the volume ratio of glycoprotein solution to sevag reagent was 1:2, time was 15min and sevag reagent was 4:1 between chloroform and butanol. The result also indicate that lactose and (NH4)2SO4 were the best carbonic and nitrogen sources for polysaccharide respectively. The polysaccharide production were 37.296mg/L and 12.961mg/L.The best conditions for extracting polysaccharide from Porphyridium purpureum were as follow: alcohol concentration was 75%, alcohol volume was 2-fold time, percolation time was 1h, the volume ratio of glycoprotein solution to sevag reagent was 1:2, time was 45min and sevag reagent was 3:1 between chloroform and butanol. The result also indicate that NaHCO3 and NH4Cl were the best carbonic and nitrogen sources for polysaccharide respectively. The polysaccharide production were 41.216 mg/L and 29.017 mg/L.The best condition for extracting polysaccharide from Porphyridium cruentum were as follow: alcohol concentration was 50%, alcohol volume was 1-fold time, percolation time was 0.5h , the volume ratio of glycoprotein solution to sevag reagent was 2:1, time was 45min and sevag reagent was 4:1 between chloroform and butanol. The result also indicate that Sodium acetate anhydrous and NH4Cl were the best carbonic and nitrogen source for polysa...