Effect Of Polysacchairdes Composition And The Related Enzymatic Analysis In Ganoderma Lucidum Submerged Culture

Ganoderma lucidum (Fr.) Krast (Polyporaceae) is a well-known traditional Chinesemushroom and is widely used as a treatment for various diseases. The polysaccharides ofGanoderma lucidum are the major substance for its biological activity and therapeuticadministration. Recent studies have showed polysaccharide possessed many interestingbiological activities, including anti-tumor, anti-inflammatory effects and cytotoxicity tohepatoma cells. Because of its perceived health benefits, G. lucidum polysaccharides haveattacted attention of researchers as a health food in Asian and other countries. In this paper,the relationship between morphology and polysaccharide production of G. lucidum insubmerged culture is studied. In addition, the biosynthetic pathways of G. lucidumpolysaccharides have been determined by analyzing the monosaccharide composition andenzyme activities in pathway. The main results are listed as follows:1. The relationship between morphology and polysaccharide production of G. lucidum insubmerged cultureIn this study, morphology of mycelium pellets were classified as S, M and L pelletaccording to diameter. The different morphology was regulated by various culture conditaionand the concentration of EPS was tested during the fermentation. The result indicated thatEPS is mainly produced by M pellets. Moreover, high concentration of glucose and lowpeptone were beneficial to the formation of M pellet and EPS production. Besied the diameterof pellet, the roundness of pellet was also analyzed and the result indicated that the EPSproduction was hardly affected by roundness. This study suggests that the morphologyregulation of G. lucidum pellet is an effective way to enhance the EPS production in largescale fermentation.2. The effect of carbon sources on monosaccharide composition of G. lucidumpolysaccharidesThe different carbon sources play an important role on monosaccharide composition andratio of G. lucidum polysaccharides in submerged culture. The largest proportion ofmonosaccharide is the carbon source used in culture medium and proportion is more than80%. Glucose, mannose and galactose were exited in different culture, while the proportion islower than10%. Moreover, arabinose, xylose and rhamnose were not detected inpolysaccharide when other monosaccharide was used as carbon source.3. The effect of carbon sources on enzyme activities involved G. lucidum polysaccharidesbiosynthesisAccording to the reported synthesis pathway of polysaccharide and our results, thepathway of G. lucidum polysaccharides synthesis was proposed. By assaying the enzyme activities, including phosphoglucose isomerase, fructose-1,6-diphosphatase, phosphomannoseisomerase, GDP-mannose pyrophosphortlase, phosphoglucomutase, dTDP-glucosepyrophosphortlase, rhamnose synthase, UDP-glucose pyrophosphorylase, UDP-Glucose-4-epimerase and UDP-glucose dehydrogenase, the pathways did exist. In addition,the activity of rhamnose synthase was shut off which indicated that it was too low todetermine.The results also demonstrated that there were other pathways to synthesis nucleotidesugars that the sugars can convert to nucleotide sugars directly by C-1kinases andpyrophosphorylases. Although these pathways about glucose, galactose, mannose andarabinose have been confirmed by bacteria and plants, we believe this pathway aboutrhamnose and xylose also existed.