Isolation, Purification, and Identification of Taxol and Related Taxanes from Taxol-Producing Fungus Aspergillus niger subsp. taxi

Abstract

The content of taxol in the bark of <i>yews</i> is very low, and this is not affordable from the environmental point of view. Thus, it is a necessity to look for alternative sources of taxol production to solve its supply. Currently, a large portion of the taxol in the market comes from chemical semi-synthesis, but the semi-synthetic precursors such as baccatin III and 10-deacetyl-baccatin III are extracted from needles and twigs of yew trees. Taxol-producing fungi as a renewable resource is a very promising way to increase the scale of taxol production. Our group has obtained a taxol-producing endophytic fungus, <i>Aspergillus niger</i> subsp. <i>taxi</i> HD86-9, to examine if <i>A. niger</i> can produce the taxanes. Six compounds from the fermentation broth of strain HD86-9 were isolated and identified by ¹H NMR, ¹³C NMR, and ESI-MS. The results showed that the six compounds included four taxane diterpenoids (taxol, cephalomannine, baccatin III, and 10-deacetyl-baccatin III) and two non-taxane compounds (β-sitosterol and flavonoid isovitexin). The study verified that the taxanes can be produced by the <i>A. niger</i>, which is very important to taxol production via chemical semi-synthesis. Additionally, the finding is potentially very significant to solve the taxol semi-synthetic precursors extracted from needles and twigs of <i>yew</i> trees, and the precursor production can be easily increased through the culture condition optimization, genetic breeding, and metabolic engineering of the <i>A. niger</i>.