Microbial metabolites - an infinite source of novel chemistry
Biodiversity is a precious source for modern biotechnology. It is a source which potentially holds innovative and sustainable solutions to a broad range of important problems for modern society. Improved cooperation between the natural product chemists and the microbiologists is an important step forward for speeding up the process of evaluating these potentialities. Further, microbiologists and natural product chemists in tropical countries, with the richest flora and fauna placed right a t their door step have a very central position. They are essential for building up international scientific cooperation, with the objective of expanding our understanding of biological and biochemical diversity, and based on this bringing forward more biological solutions. The entire process should build on a principle of fairness and equity in sharing of the benefits and respecting the State's sovereign right to its own resources. Introduction, Microbial diversity is constituting an infinite pool of novel chemistry, making up a valuable source for innovative biotechnology. So far we have only scratched the surface of it. The most recent estimates suggest that by now we only know approx. 5% of the total species of fungi and may be as little as 0.1 % of the bacteria. And among the ones already described, only a small fraction has been examined for metabolite profile. The microbial secondary metabolites can be brought in use in three different ways: the bioactive molecule can be produced directly be fermentation; or the fermentation product can be used as starting material for subsequent chemical modification (derivatization); or thirdly the molecules can be used as lead compounds for a chemical synthesis. However, the chemical composition of bioactive microbially produced compounds are often intriguingly complicated, including stereochemical diversities which in many instances will make chemical synthesis close to impossible -at least seen from an economical perspective. Examples on products which are produced by fermentation and used both with and without chemical modification in agriculture are Avermectins, Blasticidins, Kasugamycins, Validamycins etc. Examples on products which can not be used directly as fermentation product are Strobilurins and Pyrrolnitrine as both these products (in the form produced by the microorganism) are too highly affected by UV degradation. Various chemical modifications, however, stabilize the molecule. The hope is that such stabilization does not on the other hand lead to unacceptable residue problems. New Methodologies Data bases on natural products have become an important tool in the discovery process of novel metabolites. Examples on the most well known data bases are: Berdy Natural Product Data base (23.000 compounds, in English, DOS compatibility, no chemical structure given); Kitasato Microbial Chemistry Data Base (1 6.000 compounds, in Japanese, NEC compatibility, no structures given); New Kitasato Chemistry Data Base (1 6.000 compounds, in English, DOS compatibility, no structures); Chapmann and Hall (1 5.000 compounds, in English, DOS compatibility, including chemical structures); Actfund (1 0.800 compounds, in English, DOS and NEC compatible, no structures given).