FOOD SCIENCE ›› 2012, Vol. 33 ›› Issue (11): 137-141.doi: 10.7506/spkx1002-6630-201211030

• Bioengineering • Previous Articles     Next Articles

Separation and Purification of Intracellular and Extracellular Polysaccharides from Isochrysis galbana and Their Antimicrobial Activity

SUN Ying-ying,ZHOU Bao,XU Shen-zhen,LI Wen-hao,YAN Bin-lun*   

  1. (Jiangsu Key Laboratory of Marine Biotechnology, Huaihai Institute of Technology, Lianyungang 222005, China)
  • Online:2012-06-15 Published:2012-07-27

Abstract: Two crude polysaccharides, intracellular polysaccharide (IPS) and extracellular polysaccharide (EPS), were isolated from the cells and culture supernatant of Isochrysis galbana through hot-water extraction. The separation and purification of IPS and EPS, and their antimicrobial activities against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Proteus sp. were investigate, respectively. IPS was separated by ethanol-precipitation and purified by Sephadex G-75 gel chromatography, or by DEAE-52 column chromatography, while EPS was fractionated by Sephadex G-100 gel filtration chromatography. Finally, IPS and EPS were analyzed by UV and IR spectroscopy. The results indicated that: 1) IPS could inhibit the growth of Escherichia coli, Bacillus subtilis and Staphylococcus aureus. EPS could inhibit the growth of Escherichia coli and Bacillus subtilis. 2) IPS was separated into two fractions (IPS Ⅰand IPS Ⅱ) by DEAE-52 column chromatography. Both fractions could inhibit the growth of Bacillus subtilis and Staphylococcus aureus; EPS was separated by Sephadex G-100 gel filtration chromatography into three fractions (EPSA, EPSB and EPSC) with inhibitory activity against the growth of Escherichia coli; 3) The IR and UV spectra of IPS and EPS showed no ester protein, nucleic acid or pigment. Typical absorption curves of IPS and EPS revealed galactose frame with pyranglycoside linkage, while EPS did not exhibit sulfate radicals in the sugar linkage.

Key words: Isochrysis galbana, intracellular polysaccharide, extracellular polysaccharide separation and purification, antibacterial activity

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