Biotransformation of geniposide in Gardenia jasminoides to genipin by Trichoderma harzianum CGMCC 2979

Trichoderma harzianum (T. harzianum) CGMCC 2979 was used to transform the geniposide in Gardenia jasminoides (G. jasminoides) to genipin, dispensing the use of purified enzyme and the extraction of geniposide from the raw material. At 30 °C, pH 6.1, and an initial G. jasminoides concentration of 80 g dried fruit per liter of medium, the geniposide-to-genipin conversion rate reached 97.8% after 48 h of fermentation. The genipin was purified from the fermentation broth by a combined method of XAD-16N-resin and silica-gel chromatography, yielding a total recovery of 62.3%. A 74.4-kDa geniposide-β-glucosidase implicated in the transformation of geniposide to genipin was purified from T. harzianum CGMCC 2979. It had optimum activity at 50 °C and pH 4.0–5.0. The Km and Vmax of the enzyme for geniposide were 3.6 mmol/L and 775 μmol/h/mg protein, respectively. The simple, direct, and efficient biotransformation of geniposide in G. jasminoide to genipin by T. harzianum CGMCC 2979 that is described in this study could represent an alternative and effective method for producing genipin.

Graphical AbstractWe described a simple and effective method for preparing genipin based on the biotransformation of geniposide in Gardenia jasminoides by Trichoderma harzianum. The mechanism of biotransformation was also discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide