Biologically sourced products

Some hydrogen cyanide is formed whenever hydrocarbons (qv) are burned in an environment that is deficient in air. Small concentrations are also found in the stratosphere and atmosphere. It is not clear whether most of this hydrogen cyanide comes from biological sources or from high temperature, low oxygen processes such as coke production, but no accumulation has been shown (3). 

For more than two decades Woodward s total synthesis1 1 "d of chlorophyll a was in fact the only total synthetic approach to a chlorin. When, in the early eighties, new chlorin-type natural products were isolated from different biological sources, a systematic investigation of selective synthetic approaches leading to chlorins was induced.4... 

Figure 7.5 Production of xanthan gum in batch culture using X. campestris. Bacterial dry weight ( ) xanthan gum ( ) residual glucose ( ) residual glutamate (A). Adapted from Microbial exopolysaccharide, Yenton etai pp 217-261. In biomaterials Novel Materials from Biological Sources, D Byrom (Ed), MacMillan Academic Professional Ltd, 1991.

In addition to chemical-based drugs, a range of pharmaceutical substances (e.g. hormones and blood products) are produced by/extracted from biological sources. Such products, some major examples of which are listed in Table 1.2, may thus be described as products of biotechnology. In some instances, categorizing pharmaceuticals as products of biotechnology or chemical synthesis becomes somewhat artificial. For example, certain semi-synthetic antibiotics are produced by chemical modification of natural antibiotics produced by fermentation technology. 

It overcomes problems of product safety. Direct extraction of product from some native biological sources has, in the past, led to the unwitting transmission of disease. Examples include the transmission of blood-borne pathogens such as hepatitis B and C and human immunodeficiency virus (HIV) via infected blood products and the transmission of Creutzfeldt-Jakob disease to persons receiving human growth hormone (GH) preparations derived from human pituitaries. 

The domination of PET is likely to continue so long as the raw material costs remain low, and these are currently driven by the cost of oil. Although synthetic fibers use only 1 % of the petroleum stream, they are in competition for that resource with fuels which use up to 50 times as much. Chemical producers already have efforts in place to supply raw materials for PET from renewable biological sources, so it is possible that even the increasing cost of oil will not diminish the dominance of polyester. When contrasted with increasing costs of land and resources for natural fiber production, as food for an increasing population competes for the same land, the use of PET fibers will likely become even more prevalent than today. 

The C02-philic perfluoroalkyl-substituted (R,S)-3-H F -BINAPHOS ligand [34] was successfully applied to enantioselective hydrogenation in the inverted SCCO2/H2O system. The complex [Rh(cod)2]BARF was chosen as metal source and the active catalyst was formed in situ. Using the same procedure as above, similar activities and more than 98% ee were obtained consistently over five subsequent cycles in the hydrogenation of methyl 2-acetamido acrylate. The results demonstrate the potential of the inverted SCCO2/H2O system for asymmetric synthesis of chiral biologically active products. 

Novel biomarkers, i.e. tracer derivatives from unknown natural products, are sometimes encountered in geological or environmental samples, typically as hydrocarbons. The detection and determination of these compounds are usually based on the interpretation of mass spectra in GC-MS analyses. The proofs of chemical structures are based on the proposed interpretation of the MS data, separation and purification of the unknown compounds, exact structure determination by NMR methods or X-ray crystallography (if the compound is a solid that can be crystallized), and finally, comparison with a synthetic standard. The next question concerns the biological source of the biomarker precursor compound. Many biomarkers still have no proven natural product precursors nor known biological sources (e.g. perylene, tricyclic terpanes). " ... 

There are five basic sources of pharmaceuticals. By dollar value of products, fermentation is probably the most important, whereas by tonnage, chemical synthesis is dominant. Fermentation is used for antibiotics such as penicillins and tetracyclines. Chemical synthesis provides drugs such as the psychotropics and antihistamines. Animal extracts provide hormones. Biological sources lead to vaccines and serums. Vegetable extracts provide steroids and alkaloids. The top ten pharmaceutical companies in order of revenues are the following Merck, Pfizer, Bristol-Myers Squibb, Johnson ... 

Pharmaceutical substances form the backbone of modern medicinal therapy. Most traditional pharmaceuticals are low molecular mass organic chemicals (Table 1.1). Although some (e.g. aspirin) were originally isolated from biological sources, most are now manufactured by direct chemical synthesis. Two types of manufacturing companies thus comprise the traditional pharmaceutical sector the chemical synthesis plants, which manufacture the raw chemical ingredients in bulk quantities, and the finished product pharmaceutical facilities, which purchase these raw bulk ingredients, formulate them into final pharmaceutical products, and supply these products to the end-user. 

Table 2.11 Some traditional pharmaceutical products produced by/extracted from biological sources, which come under the auspices of CDER for regulatory purposes. The specific reviewing divisions within CDER which deal with these products are also listed...

Biomass for fuel production could be considered material that is either directly or indirectly derived from biological sources such as products of agriculture and forestry. As a fuel source, biomass is considered renewable and one that does not... 

Remote continental -104 Three modes centered at Dp - 0.02, 0.12, and 1.8 p, m includes products of gas-to-particle conversion and biological sources, e.g., pollens... 

It is well known that plants are an exceptional source of biologically active products which may serve as commercially significant entities in themselves, and which may provide lead structures for development of modified derivatives possessing enhanced activity and reduced toxicity. It is likely that many compounds still await discovery. However, in the last decade the source of natural drugs has expanded to include lower plants, microorganisms and animals as well as marine organisms. 

Table I (104) shows the yields of products from maltose to malto-pentaose recovered from digests of 0.2 M crystalline a-D-glucosyl fluoride with crystalline a-amylase preparations from six different biological sources. The digests were incubated at 30 °C for 10 minutes, heat inactivated, and chromatographed for product isolation and analysis.

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