Effect of Environmental Factors on the Intracellular and Extracellular Polysaccharide Production of Isochrysis galbana

Isochrysis galbana in different growth phases,pH,salinity and light intensity were analyzed.The results indicated that the algae in stationary phase(10 d) had higher intracellular and extracellular polysaccharide production.When the pH of media was maintained at 7.0,there was the highest production of intracellular polysaccharide.When pH was between 6.0 and 9.0,the extracellular polysaccharide production increased with the enhancement of pH;when salinity was between 8.25‰ and 66.00‰,the polysaccharide production of I.galbana increased with the enhancement of salinity.However,when the salinity is beyond 66.00‰,it inhibited the polysaccharide synthesis of microalgae.A higher light intensity resulted in more intracellular and extracellular polysaccharide production for I.galbana.Growth phases,pH,salinity and light intensity were key factors to control the polysaccharide production of I.galbana.Those factors had significant effect on the intracellular polysaccharide synthesis,but growth phases and light intensity significantly affected the extracellular polysaccharide synthesis.