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Batch kinetics during the exo-polysaccharide (EPS) fermentation of Ganoderma lucidum was investigated as a function of different substrates (glucose and starch), substrate concentration (1∼7%, w/v) and subculture (3 times). Logistic model for mycelial growth fitted the experimental data better than Monod and two-thirds power model. The Luedeking-Pirt equation was adequate to fit the kinetic data of product formation and substrate consumption. The EPS production was strongly non-growth associated, although it was mixed type. The product formation and substrate consumption by growth associated mechanism decreased as the concentration of glucose increased, while those of the non-growth associated mechanism increased. However, starch medium increased the growth associated and non-growth associated substrate consumption indicating higher availability of substrate. Also, batch culture in starch medium showed the higher specific growth rate and stability during subculture than those in glucose medium. In conclusion, the enhanced EPS production and stability in the subculture was found to be remarkably improved by use of starch as sole carbon source in medium. The maximum mycelium dry weight and EPS production of 9.463 and 10.410 g/ℓ, respectively, were obtained after shake culture of 7 days at 30℃ from the media containing 7% starch.
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