Biotechnological production fermentation technique

The present review work is summarized on the fermentation systems used for the biotechnological production, the various raw materials and applications of lactic acid and organic lactates. Future developments in this area with respect to the strain selection and modificatimis, genetic-engineering approaches, carbohydrate sources and their pretreatment, fermentation techniques and the downstream processing options are discussed. 

Biopolymer Extraction. Research interests involving new techniques for separation of biochemicals from fermentation broth and cell culture media have increased as biotechnology has grown. Most separation methods are limited to small-scale appHcations but recendy solvent extraction has been studied as a potential technique for continuous and large-scale production and the use of two-phase aqueous systems has received increasing attention (259). A range of enzymes have favorable partition properties in a system based on a PGE—dextran—salt solution (97) ... 

In membrane extraction, the treated solution and the extractant/solvent are separated from each other by means of a solid or liquid membrane. The technique is applied primarily in three areas wastewater treatment (e.g., removal of pollutants or recovery of trace components), biotechnology (e.g., removal of products from fermentation broths or separation of enantiomers), and analytical chemistry (e.g., online monitoring of pollutant concentrations in wastewater). Figure 18a shows schematically an industrial hollow fiber-based pertraction unit for water treatment, according to the TNO technology (263). The unit can be integrated with a him evaporator to enable the release of pollutants in pure form (Figure 18b). 

Biotechnological transformation is powerful tool to effectively utilize a broad variety of plant oils, with the aim to modify their structure for the production of new lipid-based materials with demanded properties and functions. One method of plant oil transformation is based on the direct utilization by microorganisms. Employed oils can be converted to aimed compounds by submerged cultivation or oils, and/or oleaginous plant materials can be utilized during solid state fermentation to useful bioproducts enriched with demanded microbial products. Another biotransformation technique covers the enzymatic modification of oil components to structured lipids with biological properties. 

The noted technical weaknesses are certainly not due to the total neglect of such issues and are probably not unexpected. It simply takes considerable time and effort to develop the technology to exploit the new techniques. Those who started early, developing the techniques to a level where these can be sufficiently controlled for an industrial application, are more likely to win the race to the market place. In the case of medicinal products fi om biotechnology, fermentation technology is an essential element of the technical development. In Japan this has been recognized very early and Japan s breweries have put considerable money into fermentation research. 

The use of biotechnology in the manufacture of pharmaceuticals is of increasing interest Consequently these techniques require attention in the planning of unit processes. Bioprocessing can be considered in terms of small-scale bioreactors, or fermenters, and the translation of such processes into large-scale economically viable production operations. ... 

The rapid growth of biotechnological research the last decades has emphasized the need for proper analytical techniques for bioprocess monitoring. Rapid identification and quantification of essential components in biotechnological processes is essential for process development and optimization. It has been demonstrated that improved monitoring will result in better control and thus improved productivity [20]. While most bioprocesses still are only monitored by the measurement of traditional parameters, such as CO2, pH and 02, there is an increasing need to also follow the concentrations of fermentation substrates and products [21],... 

Much effort has also been directed toward the development of fully continuous chemostat-type fermentations in which a tank produces a steady stream of enzymes. In this type of operation, product-containing fermentation broth is drawn off while new media is fed to the tank to maintain a constant volume. Reasonable successes with this method have been reported in the biopharmaceutical industry. However, similar examples of successful application of this technique have not yet appeared in the industrial biotechnology literature. 

Biotechnology has had a significant effect on the flavour industry but two factors have limited its application to fragrance. The first is cost, as biotechnological processes are usually quite expensive. The second is selectivity. Individual enzymic reactions are very selective, but biochemical redox reactions require expensive co-factors and so the usual technique is to run whole cell fermentations so as to allow the cell s chemical factory to recycle the co-factors. However, the cell does much chemistry in addition to the reaction we wish it to do and the result is a horrendous effluent problem. In flavours, the problem is often simpler as the whole cell, e.g. a yeast cell, can be used as the product. 

This book covers several of the emerging areas of separations in biotechnology and is not intended to be a comprehensive handbook. It includes recent advances and latest developments in techniques and operations used for bioproduct recovery in biotechnology and applied to fermentation systems as well as mathematical analysis and modeling of such operations. The topics have been arranged in three sections beginning with product release from the cell and recovery from the bioreactor. This section is followed by one on broader separation and concentration processes, and the final section is on purification operations. The operations covered in these last two sections can be used at a number of different stages in the downstream process. 

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