Biological/fermentative production advantages

Ultrafiltration has the advantage that there is removal of low molecular weight fermentation products and medium components during concentration of the exopolysaccharide. In addition, biological degradation is minimised because fluid is held only for a short time during the filtration process. Other advantages lie in file fact that there is no requirement for solvent recovery and the process is carried out at ambient (not elevated) temperature. 

In addition to its solvent properties, dense phase fluid carbon dioxide offers the advantage of low toxicity and low potential for environmental harm (the small amounts of greenhouse gas carbon dioxide released from its application as a solvent are negligible compared to the quantities released from the combustion of fossil fuels). A big advantage of dense phase fluid carbon dioxide is its volatility, which means that it separates readily from reaction products when pressure is released. Furthermore, carbon dioxide released from a reaction mixture can be captured and recycled for the same application. Carbon dioxide can be obtained at low cost from biological fermentation processes. 

A major selectivity advantage of biological catalysts over traditional systems includes the ability to form single products (chemical selectivity) as well as single optical isomers (stereoselectivity). Specific examples where biological routes are preferred commercially include fermentative processes for the amino acids monosodium glutamate (MSG), lysine, aspartic acid, citric acid and phenylalanine (5). Many other chemicals have also been produced by fermentative processes (6). 

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