The Effect Of Fermentation Conditions On Mycelium Morphology And Polysaccharides Biosynthesis Of Ganoderma Lucidum In Submerged Culture

Ganoderma lucidum (Fr.) Krast (Polyporaceae) is a well-known fungus in traditionalChinese medicine. Many studies have revealed that it has medicinal value because of thepresence of polysaccharides, G. lucidum acid and polypeptide. Polysaccharide as a majorvaluable metabolite possess some interesting biological activities, including hypoglycemicand hypolipidemic effect, anti-tumor and antioxidation. Extraction, structure identification,biological activities of polysaccharides and the optimization of culture conditions are the mainresearch focus. However, few works focus on morphology of mycelium pellets and synthesispathway of polysaccharides of G. lucidum. The main results are listed as follows:The relationship between mycelium morphology and EPS (Exo-polysaccharides)production of G. lucidum was investigated during submerged fermentation. Results indicatedthat the mycelium morphology and EPS production of G. lucidum was affected by regulatingfermentation conditions. Spherical mycelium pellets was the main mycelium morphologyduring submerged fermentation and classified as small, middle and large-sized pelletsaccording to diameter. Middle-sized pellet was main morphology of G. lucidum myceliumduring submerged fermentation. The high percentage of small and middle-sized pellets wasbeneficial to EPS production. Moreover, more EPS production was obtained when thepercentage of small-sized pellet was higher than the proportion of large-sized pellet.Large-sized pellet was unflarouable for accumulation of EPS.The effect of different culture conditions on monosaccharide composition of EPS andspecific activities of biosynthetic related enzymes of polysaccharides of G. lucidum wasstudied. Mole percentages of glucose, galactose and mannose of EPS and specific activities ofbiosynthetic related enzymes all changed as regulating fermentation conditions. The tendencyof mole percentages of galactose and mannose was similar to the trend of specific activities ofrelated enzymes, then relationship between specific activities of related enzymes and molepercentages of mannose and galactose was analyzed. The results suggested that PGM, UGPG,PGI and PMI could be important enzymes of the biosynthetic pathway of sugar nucleotide ofEPS from G. lucidum.The effect of different fermentation conditions on anti-tumor activity of polysaccharidesof G. lucidum was investigated. EPS were obtained as experimental samples under differentfermentation conditions, which were tested on their in vitro effect on Hepa1-6andMDA-MB-231cell line respectively. The results indicated that different fermentationconditions had important impacts on anti-tumor activity of G. lucidum polysaccharides.Polysaccharides obtained under30°C, low pH and rotating speed could perform strongerinhibition on Hepa1-6and MDA-MB-231cells. The trend of impact of fermentationconditions on anti-tumor activity of polysaccharides of G. lucidum could not be changed indifferent fermentation time.