Optimization of the production process for the anticancer lead compound illudin M: process development in stirred tank bioreactors

Fungi: Pioneers of chemical creativity - Techniques and strategies to uncover fungal chemistry

Natural product discovery from fungi for drug development and description of novel chemistry has been a tremendous success. This success is expected to accelerate even further, owing to the advent of sophisticated technical advances of technical advances that recently led to the discovery of an unparalleled biodiversity in the fungal kingdom. This review aims to give an overview on i) important secondary metabolite-derived drugs or drug leads, ii) discuss the analytical and strategic framework of how natural product discovery and drug lead identification transformed from earlier days to the present, iii) how knowledge of fungal biology and biodiversity facilitates the discovery of new compounds, and iv) point out endeavors in understanding fungal secondary metabolite chemistry in order to systematically explore fungal genomes by utilizing synthetic biology. An outlook is given, underlining the necessity for a collaborative and cooperative scenario to harness the full potential of the fungal secondary metabolome.

Spore-Derived Isolates from a Single Basidiocarp of Bioluminescent Omphalotus olivascens Reveal Multifaceted Phenotypic and Physiological Variations

The fungal genus Omphalotus is noted for its bioluminescence and the production of biologically active secondary metabolites. We isolated 47 fungal strains of Omphalotus olivascens germinated from spores of a single mushroom. We first noted a high degree of variation in the outward appearances in radial growth and pigmentation among the cultures. Radial growth rates fell into at least five distinct categories, with only slower-growing isolates obtained compared with the parental dikaryon. Scanning UV-vis spectroscopy of liquid-grown cultures showed variation in pigmentation in both the absorption intensity and peak absorption wavelengths, indicating that some isolates vary from the parental strain in both pigment concentration and composition. Bioluminescence intensity was observed to have isolates with both greater and lesser intensities, while the increased emission in response to caffeic acid was inversely proportional to the unstimulated output. Under UV illumination, the media of the parental strain was observed to be brightly fluorescent, which was not due to the pigment, while the isolates also varied from greater to lesser intensity and in their peak emission. At least three separate fluorescent bands were observed by gel electrophoresis from one of the cultures, while only one was observed in others. In a subset of the cultures, fluorescence intensity varied significantly in response to casamino acids. None of this subset produced an antibiotic effective against Staphylococcus aureus, and only the haploids, but not the parental heterokaryon, produced an antibiotic consistent with illudin M effective against Mycobacterium smegmatis. This same subset produced an anticancer agent that was highly potent against MDA-MB-468 breast cancer tumor cells. We interpret these variations in haploids as significant in altering Omphalotus physiology and its production of secondary metabolites, which may in turn alter their ecology and life cycle, and could be further applied to studying fungal physiologies and facilitate linking them to their genetic underpinnings.

Scaling up for success: from bioactive natural products to new medicines

Covering 1986 to presentNatural product drug discovery at Novartis has a long and successful history of delivering life saving medicines to millions of patients. In this viewpoint, we are presenting the tools we use and challenges we face as we advance natural products from early research into development and beyond. We are leveraging our collection of 90 000 microbial strains and 20 000 isolated natural products to find new medications in an interdisciplinary approach that requires expertise in microbiology, computational biology, synthetic biology, chemistry, and process development. Technological advances, particularly in genome engineering and data science have transformed our field, accelerating discovery and facilitating sustainable compound supply. Emerging new modalities such as antibody drug conjugates, radioligand therapies and xRNA-based medications offer new opportunities for natural product-derived drugs. By taking advantage of these new modalities and the most recent research technologies, natural products will significantly contribute to the medicines of the future.

Optimization of the production process for the anticancer lead compound illudin M: downstream processing

Background

Secondary metabolites have played a key role as starting points for drug development programs due to their often unique features compared with synthetically derived molecules. However, limitations related to the discovery and supply of these molecules by biotechnological means led to the retraction of big pharmaceutical companies from this field. The reasons included problems associated with strain culturing, screening, re-discovery, purification and characterization of novel molecules from natural sources. Nevertheless, recent reports have described technical developments that tackle such issues. While many of these reports focus on the identification and characterization of such molecules to enable subsequent chemical synthesis, a biotechnological supply strategy is rarely reported. This may be because production processes usually fall under proprietary research and/or few processes may meet the requirements of a pharmaceutical development campaign. We aimed to bridge this gap for illudin M—a fungal sesquiterpene used for the development of anticancer agents—with the intention to show that biotechnology can be a vital alternative to synthetic processes dealing with small molecules.

Results

We used µL-scale models to develop an adsorption and extraction strategy for illudin M recovery from culture supernatant of Omphalotus nidiformis and these findings were successfully transferred into lab-scale. By adsorbing and eluting the product using a fixed resin-bed we reduced the working volume by ~ 90% and removed the aqueous phase from the process. After a washing step, a highly concentrated illudin M fraction was obtained by isocratic elution with 80% methanol. The fraction was dried and extracted using a water/heptane mixture, enriching illudin M in the heptane phase. From heptane illudin M could be instantly crystalized by concentrating the solution, achieving a final purity > 95%.

Conclusion

We have developed a robust, scalable and low-cost downstream process to obtain highly pure illudin M. By using solid phase extraction we reduced the production of solvent waste. Heptane from the final purification step could be recycled. The reduced amounts of solvents required, and the short purification time render this method a very economic and ecologic alternative to published processes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-022-01886-2.