Sustainable production of camptothecin from an Alternaria sp. isolated from Nothapodytes nimmoniana
Camptothecin the 3rd most sought after alkaloid, is commercially extracted in India in the endangered plant, Nothapodytes nimmoniana. Endophytes, the microorganisms that reside within plants, are reported to be capable of produce host-plant connected metabolites. Hence, our research aims to determine a sustainable and camptothecin yielding endophyte, as a substitute source for commercial manufacture of camptothecin. As many as 132 endophytic yeast strains were isolated from various plant parts (leaf, petiole, stem and bark) of N. nimmoniana, of that 94 put together to create camptothecin in suspension culture. Alternaria alstroemeriae (NCIM1408) and Alternaria burnsii (NCIM1409) shown camptothecin yields as much as 426.7 ± 33.6 µg/g DW and 403.3 ± 41.6 µg/g DW, correspondingly, the greatest reported production up to now. Unlike the reported product yield attenuation in NSC-100880 endophytes with subculture in axenic condition, Alternaria burnsii NCIM1409 could retain and sustain producing camptothecin as much as ~ 200 µg/g despite 12 continuous subculture cycles. The camptothecin biosynthesis in Alternaria burnsii NCIM1409 was confirmed using 13C carbon labelling (and cytotoxicity analysis on several cancer cell lines) which strain is now able to accustomed to create a sustainable bioprocess for in vitro manufacture of camptothecin instead of plant extraction.