Camptothecin-producing endophytic fungus Trichoderma atroviride LY357: isolation, identification, and fermentation conditions optimization for camptothecin production

Abstract

Camptothecin (CPT), the third largest anticancer drug, is produced mainly by Camptotheca acuminata and Nothapodytes foetida. CPT itself is the starting material for clinical CPT-type drugs, but the plant-derived CPT cannot support the heavy demand from the global market. Research efforts have been made to identify novel sources for CPT. In this study, three CPT-producing endophytic fungi, Aspergillus sp. LY341, Aspergillus sp. LY355, and Trichoderma atroviride LY357, were isolated and identified from C. acuminata. Most CPT produced by these fungi was found in the fermentation broth, and their corresponding CPT yields were 7. 93, 42.92, and 197.82 μg l −1 , respectively. The CPT-producing capability of LY341 and LY355 was completely lost after repeat subculturing. A substantial decrease of CPT production was also observed in the second generation of LY357. However, a stable and sustainable production of CPT was found from the second generation through the eighth generation of LY357. The fermentation medium, time, pH, temperature, and agitation rate were optimized for CPT production. Methyl jasmonate and XAD16 were proven to be an optimum elicitor and adsorbent resin, respectively, in view of that CPT yield was increased 3.4-and 11-fold through their use. A 50-to 75-fold increase of CPT yield was obtained when the optimized fermentation conditions, elicitor, and adsorbent resin were combined and applied to the culture of the seventh and eighth generations of LY357, and the highest CPT yield was 142.15 μg l −1 . The CPTproducing T. atroviride LY357 paves a potential to uncover the mysteries of CPT biosynthesis.

Production of valuable compounds by molds and yeasts

“…The endophytic fungus produced 142 μg l − 1 of camptothecin in the presence of the elicitor methyljasmonate and XAD adsorbant resin. 75 Type 1 DNA topoisomerase has been identified as the cellular target of camptothecin. When patients become resistant to irinotecan, its use can be prolonged by combining it with the monoclonal antibody Erbitux (Cetuximab).…”

Isolation and characterization of Paenibacillus polymyxa LY214, a camptothecin-producing endophytic bacterium from Camptotheca acuminata

“…Following the same experimental procedure as that for the isolation of CPT-producing T. atroviride LY357 [13], the different plant parts of C. acuminata were placed on the Petri dishes containing Gause medium G-1 agar (GA1A), potato dextrose agar (PDA), Sabouraud dextrose agar (SDA), and water agar (WA), respectively. Total 125 endophytes, including 40 from roots, 43 from stem barks, 12 from leaves, and 30 from twigs, were isolated and maintained on the isolation medium.…”

Endophytic fungi residing in medicinal plants have the ability to produce the same or similar pharmacologically active secondary metabolites as their hosts

“…A similar situation appears to hold for CPT-producing fungi (Pu et al, 2013) and HupA-producing endophytic fungi suggesting a horizontal transfer of large secondary metabolism gene clusters between fungi. Several studies off er support to this idea; the complete sterigmatocystin gene cluster in Podospora anserine was horizontally transferred from Aspergillus (Slot and Rokas, 2012).…”

“…and Fomitopsis sp., were identifi ed as CPT-producers with the highest yield of CPT being obtained from A. alternata (73.9 μg/g DW) . CPT-producing endophytic fungi have also been isolated from C. acuminata (Pu et al, 2013) and N. nimmoniana (Bhalkar et al, 2016).…”