Modulation of <i>Porphyridium aerugineum</i> polysaccharide rheology by aqueous extract of a garden soil

Abstract

A stock (0.5% w/v) aqueous solution of the polysaccharide of the microalga Porphyridium aerugineum was further diluted using (i) deionized water and (ii) an aqueous (0.2% w/v) solution of a new, garden soil extract. The viscosity of the resultant solution was higher by about 23% (5 samples) where the soil extract was used. The viscosity of the soil extract alone was very low i.e., 0.62 ± 0.074 centipoise for a 0.2% w/v solution. It is indicative that the soil extract may be acting synergistically to change the conformation of the algal polysaccharide chain molecules, resulting in the observed higher viscosity. The soil extract also enhanced thermostability of low aqueous solutions of the P.aerugineum polysaccharide. A comparison of the Infra Red (IR) spectra of the new soil extract and the P.aerugineum shows that the two substances are essentially different. With this new soil extract the mechanism of synergism in the rheology of the P.aerugineum polysaccharide can be further elucidated and exploited for commercial, food and industrial applications.


KEY WORDS: P.aerugineum, polysaccharide, rheology, soil extract


Global Jnl Pure & Applied Sciences Vol.10(2) 2004: 235-238