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

Abstract

Camptothecin (CPT) is mainly produced and extracted from Camptotheca acuminata and Nothapodytes foetida for pharmaceutical use, i.e., the starting material for chemical conversion to the clinical CPT-type drugs. As the third largest plant anticancer drug, the heavy demand on CPT from global market leads to many research efforts to identify new sources for CPT production. Herein we report the isolation and characterization of a CPT-producing endophytic bacterium Paenibacillus polymyxa LY214 from Camptotheca acuminata. A 10.7 μg l−1 of CPT was presented in the fermentation broth of P. polymyxa LY214. Its CPT production decreased sharply when the strain of the 2nd generation of P. polymyxa LY214 was cultured and fermented. However, the CPT production remained relatively constant from 2.8 μg l−1 of the 2nd generation to 0.8 μg l−1 of the 8th generation of P. polymyxa LY214 under optimized fermentation conditions. A 15- to 30-fold increase of CPT yield was observed when the optimized fermentation conditions, together with the addition of putative biosynthetic precursors of CPT and adsorbent resin XAD16, were applied to ferment the strains of the 7th and 8th generation of P. polymyxa LY214. Bioinformatics analysis of the relative species of P. polymyxa LY214 indicates its potential to produce CPT, which will be helpful to decipher the mysteries of CPT biosynthesis.

Enhanced production of camptothecin and biological preparation of N 1-acetylkynuramine in Camptotheca acuminata cell suspension cultures

“…Previous works on the CAM-producing endophytes suggested that CAM production will be attenuated with subsequent successive subculturing and fermentation (Pu et al 2013;Pu et al 2015). A similar CAM production attenuation was observed when the C. acuminata cell suspension cultures were successively subcultured and grown in the same axenic conditions ( Supplementary Fig.…”

“…The heavy demand for CAM derivatives has resulted in destructive harvesting of C. acuminata, the CAM-producing plant in China, and it was claimed to be a protected plant species in China (http:// www.gov.cn/gongbao/content/2000/content_60072.htm). Thus, identifying new sources of CAM and novel production methods are urged in the science community (Bhalkar et al 2016;Deepthi and Satheeshkumar 2016;Pu et al 2013;Pu et al 2015;Vasanthakumari et al 2015;Venugopalan and Srivastava 2015;Venugopalan et al 2016).…”

The isolation of water-soluble natural products – challenges, strategies and perspectives

“…192 The production of camptothecin ( 26 ) by the endophyte Paenibacillus polymyxa LY214 could be enhanced 30× by the addition of secologanin, tryptamine and XAD-16. 193 Polyene antifungals are of difficult isolation due to their amphiphilic nature. 194 A new method was devised for the isolation of amphotericin B ( 27 ) analogues and of truncated amphotericin B biosynthesis intermediates by the use of XAD-16, which considerably improved the recovery of 27 derivatives from culture media.…”

Plant Endophytes and Epiphytes: Burgeoning Sources of Known and “Unknown” Cytotoxic and Antibiotic Agents?

“…In the introduction to their paper in 2015, Pu et al gave a short history of reports of endophytic microbes that could produce camptothecin on isolated culture [57], but in almost all cases, the yields decreased with subculture. However, they had reported 2 years earlier that one of their isolates, Trichoderma atrovide LY357, did show increased yields when elicitors/adsorbent resins were added to the culture broth [58].…”