Production of polysaccharides from Ganoderma lucidum (CCRC 36041) under limitations of nutrients

This research studied the production of polysaccharides from Ganoderma lucidum under the various limitations of nutrients, including carbon-source, nitrogen-source, phosphate-source, magnesium-source, and dissolved oxygen. The different responses of polysaccharide production were observed under different limitations of nutrients. The concentration of polysaccharides was from 1.79 g/L decreasing to 0.91 g/L when the concentration of glucose was from 60 g/L decreasing to 20 g/L. The highest specific polysaccharide production was found at 60 g/L glucose media with 0.299 g/g-cell, and the lowest molecular weight was found in carbon-source limitation. Under nitrogen-source limitation the concentration of cells was low, but both polysaccharide production (1.61 g/L) and specific polysaccharide production (0.492 g/g-cell) were the highest. The lowest molecular weight of polysaccharides was found under nitrogen-source limitation. Both the phosphate-source and magnesium-source limitations showed low cell growth. With the phosphate-source limitation both low polysaccharide production and a lower molecular weight of polysaccharides was found. In the magnesium-source limitation low polysaccharide production, but a higher molecular weight of polysaccharides, was found. For the factor of oxygen supply the best polysaccharide production was found with sufficient oxygen for the first 5 days’ cultivation and then, after changing to oxygen limitation for another 5 days’ cultivation. On the other hand, the highest molecular weight of polysaccharides was found from the beginning with oxygen limitation throughout the process of fermentation.