Biocatalysis fermentation processes

Bruggink (1996) has given an account of how the production of cefalexin, which is the largest cephalosporin in the market, can be converted from a ten-step process based on benzaldehyde and penicillin into a six-step process where biocatalysis is involved in three steps. The wastewater stream, containing 30-40 kg of unwanted materials in the conventional process, has been substantially reduced. Similarly, Van Loon et al. (1996) have given details of fermentation processes for cleaner and cheaper compared to the process practised so far. 

Industrial catalysis, based on man-made catalysts, developed its own history which is briefly summarised in Section 1.2. The roots of biocatalysis and biocat-alytic processes are completely different, notwithstanding the early recognition that fermentation processes are in essence of a catalytic nature. The relationship between biocatalysis and organic chemistry is close. It is really quite recently that biocatalysis and man-made catalysis have become part of the same context. This is mainly the result of increasing interest in catalytic applications to fine chemicals. 

The power of directed evolution is now well documented. These methods are robust and are able to improve industrial enzymes in reasonably short times. The first laboratory-evolved enzymes are now used commercially in laundry detergents12011 other commercial applications are on the horizon. Directed evolution may well help move biocatalysis from an enabling tool to a lowest cost approach . It also offers new opportunities to engineer multi-enzyme pathways and even whole microbes [69- 224> 2251, which will lead to straightforward single-pot, multi-enzyme bioconversions and new fermentation processes based on green resources such as glucose or inexpensive waste materials. 

Bio-Technical Resources (Manitowoc, WI) Development of microbial fermentation and biocatalysis-based processes... 

Biotechnological processes can be divided into fermentation processes and biotransformations. In a fermentation process products are formed as primary or secondary metabolites by microorganisms or higher cells from components in the fermentation broth. Product examples are amino acids, vitamins or antibiotics such as penicillin or cephalosporine. In these cases co-solvents are sometimes used for m situ product extraction. The term biotransformation or biocatalysis is used for processes where a starting material (precursor) is converted into the desired product... 

As described in Section 4.2, traditional biotech processes—namely, biocatalysis and microbial fermentation—are used for the production of small molecules, whereas the modern cell culture methodology allows the production of HMW biopharmaceuticals. A growth rate of 10-15% per annum is expected for the biotechnological contribution, while the average increase of the pharmaceutical market remains below 10%. In terms of technologies, the demanding mammalian cell cultures are expected to grow fastest, followed by microbial fermentation. 

The perspectives for an increasing use of biotechnology processes (biocatalysis, microbial fermentation) for LMW fine chemicals are promising. Substitution of traditional chemicals by biotechnology processes constitutes the most important means for reduction of manufacturing cost for existing fine chemicals. By 2010,30-60% of fine-chemical production processes are expected to comprise a biotechnology step ... 

M. Zlokarnik. Dimensional Analysis, Scale-Up. In Encyclopedia of Bio process Technology Fermentation, Biocatalysis, Bioseparation. Vol. 2, 840-861. (M.C. Flickinger and S. W. Drew, eds.) Wiley, 1999. 

Figure 30.12 represents a cell factory model to produce several categories of products via fermentation and biocatalysis processes. Industrial-scale manufacturing aspects such as uses, synthesis methods, and costs of some of these products are reviewed below as well as in Chapter 32. 

Examples of biotech-based processes and products that are already to be found are biocatalysis and biomolecules in fine chemicals, biopolymers as substitutes for synthetic polymers, enzymes and modified additives in specialties, and modern fermentation as a production process for basic and intermediate organics. The market for biotech-based products (excluding traditional fermentation in, for ex-... 

Mechanism and kinetics in biochemical systems describe the cellular reactions that occur in living cells. Biochemical reactions involve two or three phases. For example, aerobic fermentation involves gas (air), liquid (water and dissolved nutrients), and solid (cells), as described in the Biocatalysis subsection above. Bioreactions convert feeds called substrates into more cells or biomass (cell growth), proteins, and metabolic products. Any of these can be the desired product in a commercial fermentation. For instance, methane is converted to biomass in a commercial process to supply fish meal to the fish farming industry. Ethanol, a metabolic product used in transportation fuels, is obtained by fermentation of corn-based or sugar-cane-based sugars. There is a substantial effort to develop genetically modified biocatalysts that produce a desired metabolite at high yield. 

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