Increase the yield of 4-AAQB in the mycelium of Antro-dia cinnamomea with isoprenoid chain precursor and lac-tonization promotion

• Main Authors: Yi-Jun Chen, 陳奕均
• Other Authors: Been-Huang Chiang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/ars8ha

碩士 === 國立臺灣大學 === 食品科技研究所 === 107 === 4-acetylantroquinonol B (4-AAQB) and Antroquinonol (AQ) are two of the most iconic ubiquinones from the mycelium of Antrodia cinnamomea (AC). 4-AAQB has been proven to be more effective in inhibiting the growth of liver cancer cells than AQ. Therefore, the objective of this study was to increase the yield of 4-AAQB during cultiva-tion of AC. The dividing step in the biosynthetic pathways of 4-AAQB and AQ is farne-sylation of benzoquinone rings. The benzoquinone rings are either farnesylated with far-nesylpyrophosphate (FPP) or FPPB, the suffix B represents γ-lactone modification at the end of FPP. The hypothesis of this study was that FPPB are formed by lactonization of FPP. Hence, we supposed that if the lactonization process could be accelerated, then the yield of 4-AAQB would be increased and the yield of AQ decreased. Since acidic condi-tion favors the formation of γ-lactone, the effect of pH adjustment of the culture medium on the yields of 4-AAQB and AQ were investigated, and the effect of addition of farnesol as a precursor to FPP and FPPB was also studied. We expected that combination of these two treatment would further increase the yield of 4-AAQB. UPLC quantitative analysis has shown that adjusting the pH of the broth to 2.75 at the 14th day during fermentation could significantly increase the yield of 4-AAQB and decrease the yield of AQ. Further analyses of the biosynthetic intermediates by LC MS/MS revealed that farnesylation and O-methylation of the intermediates for the biosynthesis of both 4-AAQB and AQ were promoted by pH adjustment, but ketone group reduction and acetylation of benzoquinone rings were not affected. This phenomenon could mean that the reaction of FPP lactonized to FPPB was promoted. LC MS/MS analyses also showed that addition of 0.1% farnesol could increase farnesylation steps for the synthesis of both 4-AAQB and AQ, but it strongly inhibited the benzoquinone rings modification on AQ side of biosynthetic path-way, especially the conversion of CoQ3 to AQ. On the other hand, addition of farnesol did not affect too much on 4-AAQB side of biosynthetic pathway. Consequently, addition of farnesol during fermentation significantly reduced the yield of AQ but did not affect the yield of 4-AAQB. The results of this study suggested that pH adjustment could promote lactonization of FPP to formed FPPB. It seems promising to find a proper way to adjust pH and add farnesol at the same time to further increase the yield of 4-AAQB.