The Effects Of Elicitors On The Biosynthesis Of Triterpenoids By Inonotus Obliquus Under Submerged Culture

Inonotus obliquus known as “the brown Lingzhi” in China is a white rot fungus,which possesses very high medicinal value and it has many similar effects ofGanoderma lucidum, such as anti-tumor, anti-immune, hypoglycemic, antioxidationand so on. Recently, this fungus was paid attention by the academic world widely.Currently, this fungus was culture by the shake flask, and can produce the priority ofprimary metabolites, but the accumulation of various of secondary metabolites areunable to achieved the ideal level.In recent years, the addition of elicitors is a good strategy which has been widelyused in plants and fungi such as Ganoderma lucidum, which can promote myceliagrowth and accumulation of secondary metabolities. This paper makes use of twoways which are a complex medium and the addition of elicitor to improve biomassand triterpenoids production analyse comparatively the effects of triterpenoidsproduction by submerged fermentation.The results were as follow:1. The studies showed that the use of complex medium could obtain the moremycelium and total triterpenoids contents that were significantly superior to those ofthe basal medium, the mycelium and total triterpenoids contents achieved themaximum on day9, which were10.31±0.31g/L and74.98±3.18mg/g Mycelium DryWeight. Compared to those of the basal medium, the complex culture was increase by10.1%and15.5%. It was proved that the use of complex medium was a method toprove the triterpenoids production. Meanwhile, we analysed crude triterpenoidsextract which has the concentration of total triterpenoid during0.5-3.5mg/mL. Wefound that the IC50value of total triterpenids extract in complex medium was lowerthan those in basal medium, which means that the total triterpenids in complexmedium has the stronger antioxidant axtivity. 2. Methyl jasmonate (MeJA) as an effective signal molecule can study the effect oftriterpenoids by the different stages and different solvent. The results of researchshowed that the addition of50μM MeJA (tween-20as a solvent) on the6thday couldpromote the triterpenids production and obtain the best efficiency, and the value was81.74±2.46mg/100mL. However, the mycelium has a certain extent inhibition, andthe biomass was just8.48±0.11g/L. When50μM MeJA (tween-80) was added to themedium on6thday, it is more conducive to promote the mycelium and the yield oftotal triterpenoids, which were achieved the maximum by10.14±0.2g/L and100.72±2.29mg/100mL. These results exhibit MeJA (tween-80) was the best elicitorand tween-80was the best agent that can dissolve MeJA.3. Three kinds of fatty axids (linoleic acid, and palmitic acid) were added to themedium to effect the accumulation of triterpenoids from Inonotus obliquus. Theresults exhibit that all of tree fatty acids can promote the total triterpenoid productionwhile the extent of accumulation exist some difference. In terms of the mycelium andtotal triterpenoids production, the addition of oleic acid on6thday at the concentrationof1.5mg/L, the effect of total triterpenoids production was the maximum, which was94.71±1.42mg/100mL when the maximal biomass was1.13±0.03g/100mL.4. The five individual triterpenoids of mycelium was analyzed by HPLC. Comparedto the basal medium, betulin, trametenolic acid, inotodiol,3β-hydroxy-lanosta-8,24-dien-21-al and lanosterol which were maximum in the complex medium wasincreased by3.3-,2.1-,0.6-,1.0-, and1.6-fold. When MeJA (tween-80) was added tothe medium, the individual triterpenoids was increased by20.9-,5.0-,3.6-,4.2-, and3.7-fold. However, oleic acid as the best inducer among the fatty acids can alsopromote mycelium and total triterpenoids production, and the maximal value was18.3-,4.1-,2.5-,2.6-, and1.76-fold. The above results showed the various kinds o felicitors have different inducing effect of the triterpenoids.In summary, the addition of oleic acid to the culture medium during fermentationmakes the mycelia maximum. However, it seems that MeJA (Tween-80as a solvent)was added to medium, the yield of total triterpenoids and the contents of individualtriterpenoids from Inonotus obliquus was relatively high. Taking the above two factors into account, MeJA (Tween-80as a solvent) was the best elicitor promoting theproduction of triterpenoids.