Liquid Fermentation And Purification Of Ganoderic Acids

Ganoderic acids (GA), production by Ganoderma lucidum, is a physiological active compounds and applied in acesodyne, nervous systrm, antihistaminic activity, detoxification, liver protection antitumer etc. In order to realize industrial production of GA from Ganoderma lucidum, qualitative and quantitative analysis of GA, the effect of environmental conditions, isolation and extraction and structural identification were investigated in detail. The main results were described as follows:1. The qualitative determination of GA was developed by thin-layer-chromatography(TLC).. In this method, methylbenzene: ETOAC: acetic acid (13:4:0.4) was utilized as developing solvent, and 10% sulfuric acid-ETOH as derivatization reagent. Three spots R_f 0.17, R_f 0.56, R_f 0.70 was appeared , and their color change from yellow to red , purple and brown along with increase of developing time.2. In the other hand, the ultraviolet photometric method for quantitative determination of GA has been suggested. The method was proved to have the advantages of easy operation, high accuracy , well repeatability and good recovery. The standard curve is C=(0.331×A254-0.004)×n,linear correlation coefficient of the standard curve is 0.9998. The relative standard deviation of precision, ruggedness and recovery experiment is 0.56%, 3.6%, 1.1%, respectively.3. The effects of dissolved oxygen (DO) on the production of GA were investigated and a optimum DO control strategy were recommended. When the shaker speed from 175 rpm(0～48) to 75rpm(48～96 h), the concentration of biomass, extracellular GA and intracellular GA increased 10.8%, 14.5% and 23.5%, respectively, compared with that of uncontrolled culture. On the other hand, when the shaker speed from 125rpm(0～96) to zero(0～60), the concentration of biomass, extracellular GA and intracellular GA increased 4.6%, 56.1% and 30.7%, respectively, compared with that of uncontrolled culture.4. The effect of pH on GA production was investigated in batch submerged fermentation, a highest mycelial growth (11.14 g/L) was achieved at natural pH, but a highest GA concentration (538.01 mg/L) was reached at the pH 4.5. Based on result analysis, a two-stage pH-control strategy was proposed, in which pH was uncontrolled in the first stage, when pH switched to 4.5, pH was controlled at constant pH 4.5. High yield of EGA (378.53 mg/L) and high yield of IGA (216.03 mg/L) were achieved by applying this strategy. The yield of EGA and IGA were improved by 7.5% and 3.4%, respectively.