Effect of sulphate supplementation on polysaccharide production and composition in two Porphyridium cruentum strains
Year: 2007
Type: conference-paper
Abstract: The marine microalga Porphyridium cruentum is of high commercial value because of its products.The main compounds produced are sulphated exopolysaccharides (EPS), polyunsaturated fatty acids (PUFA) and phycoerythrin, a red proteinaceous pigment (1).The easy growth conditions make the use of this alga very appealing.Many studies have been conducted to determine the chemical and physical properties of EPS due to its antiviral activity as described by Huleihel M. et al 2 .This activity seems to be directly correlated with the polysaccharide degree of sulphation (3).The aim of this study was to improve polysaccharide production by P. cruentum.Different sulphate ions concentrations were tested.Further studies are going to be carried out to determine the effect of the sulphate supplementation in the polysaccharide structure. Material and Methods Two Porphyridium cruentum strains, one from Department of Biotechnology Engineering of Ben-Gurion University -Negev, Israel (ISR)and the other from Department of Microbiology -Pharmacy Faculty of University of Santiago, Spain (ESP), were grown in batch cultures in sterile conditions.The cells were cultured in 1L flasks, with constant temperature (25ºC), continuously illuminated (30mE .s -1.m -2 ) and aerated with sterile air.The growth was monitored by dry weight.The supplementation of sulphate ions was conducted by addition of magnesium sulphate and magnesium chloride was used as magnesium control.The EPS extraction was accomplished by precipitation with two volumes of ethanol.After centrifuging the culture at 10000rpm, 4-10ºC for 20-30min, the sample was placed in a water bath at 80ºC and after 1 hour it was filtrated.The EPS was lyophilized before and after a dialysis procedure.The carbohydrate and uronic acid composition were determined colometrically with a Shimadzu UV-1601 by the phenol-sulphuric acid (4) and MHDP (5) methods using galactose and glucuronic acid as standards, respectively.The sulphate content was determined turbidimetrically as barium sulphate (6) using the same spectrometer mention above.
Authors: Sousa, A. M., Silva, C., Raposo, M. F. J., Morais, R. M.
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1508055424