Effect of Phosphate on Cell Growth and Polysaccharide Production by Suspension Cultures of Protocorm-like Bodies of Dendrobium huoshanense

The effect of inorganic phosphate on the cell growth and accumulation of polysaccharides together with nutrient utilization was investigated in suspension cultures of protocorm-like bodies of Dendrobium huoshanense. Thirty-day-old cells were transferred into a liquid medium with the inoculum density of 100 g/L cells. The results indicated that the optimal concentration of phosphate in the medium for the growth of protocorm-like bodies of Dendrobium huoshanense was 2.5 mmol/L and the biomass was 496.5 g/L (fresh weight). The phosphate was a limiting factor for the cell growth and there was a relationship between the levels of intracellular phosphate and the cell growth. A total of 2.5 mmol/L of medium phosphate was beneficial to the absorption of carbon and nitrogen source. A total of 0.312 mmol/L of medium phosphate was better for the accumulation of polysaccharides and the production of polysaccharides was 2.22 g/L on day 36.