| Fungal mushroom polysaccharides are good immunomodulators, which can inhibit the tumor/cancer cell growth or virus infection in vivo without any damage to the normal cell. However, not all the fungal mushroom polysaccharides exhibit anti-tumor activity. (1-)-B-D-glucans from different fungi have different bioactivity even if they have the same chemical structure. It has been reported that the receptor proteins on the surface of the cells have different conformation and show specific recognition capability to the chain conformation of polysaccharides. Therefore, the chain conformation of the polysaccharides in solution is more important to their bioactivity than the chemical structure. The molecular mass, molecular size and chain conformation of polysaccharides in solution (stiff chain, random coil, single-, double- or triple helix, aggregate) are mainly characterized by polymer solution theory and modern method in polymer science. And the culture of the fungi, isolation, purification and bioactivity of the polysaccharides are involved in the fields of biology and medicine. Therefore, this research dealing with the structure, chain conformation and their correlation to bioactivities is in a cross field of polymer and biochemistry, and is becoming one of the international cutting-edge research fields. In this thesis, the different mycelia of Poria cocos were cultured through submerged fermentation in shake flask cultures and pilot-scale production. Then the water-soluble and alkali-soluble polysaccharides were extracted and purified from the mycelia of Poria cocos by biotechnics, and their derivatives were prepared. The chemical structure, chain conformation in solution, anti-tumor activities of the polysaccharides and their derivatives were studied, and their cellular mechanism and the correlation between structure and bioactivities were discussed.The innovative points of this work are as follows. (1) The effects of culture media on chemical composition, molecular mass and chain conformation of six polysaccharides from the mycelia of Poria cocos were clarified for the first time. (2) It has been first revealed that the water-soluble polysaccharides from the mycelia of Poria cocos from different strains and culture media exhibited different anti-tumor activity, and the heteropolysaccharides from Poria cocos mycelia cultured with wild strain in the medium containing corn steep liquor exhibited the highest anti-tumor activity against Sarcoma 180 (S-180) in vivo. (3) Water-insoluble polysaccharide PCM3-I was demonstrated to be (1-3)-a-D-glucans and exists as a relatively extended flexible chain in the 0.25 M LiCl/dimethylsulfoxide (DMSO) solution. (4) It has been revealed that sulfated glucan obtained from water-insoluble PCM3-I exhibited good water-solubility and chain stiffness as well as anti-tumor activity. The sulfated derivatives of PCM3-I showed obvious inhibition effect to the MCF-7 human breast cancer cell without any damage to the normal mammalian cells, and arrested cell cycleprogression at G0/G1 phase, and induced apoptosis in MCF-7 breast cancer cells. (5) Pilot-scale production of the mycelia of Poria cocos from wild strain was carried out in 50-liter fermenter successfully for the first time, and the heteropolysaccharides from the cultured mycelia also exhibited obvious antitumor activities. (6) The microcapsules of chitosan / sodium carboxymethyl cellulose (NaCMC) were successfully prepared by using a novel method of emulation-phase separation. The microcapsules encapsulated with Bovine serum albumin (BSA) possessed pH-sensitive release function.The main contents and conclusions in this thesis are divided into the following parts. Mycelia of a wild strain Poria cocos were cultured by two media differed in one constituent: bran extract or corn steep liquor and designated as wb and we, respectively. Six polysaccharide fractions were isolated sequentially from the two mycelia by 0.9% NaCl (PCM1), hot water (PCM2), 0.5 M NaOH (PCM3-I and -II) and 88% formic acid (PCM4-I and -II), and exo-polysacchr...
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