Genetic engineering techniques

Progress in fermentation technology has made it possible to raise the accumulation and the yield of L-glutamic acid above 100 g/L and 60% based on the total amount of sugar. AppHcation of genetic engineering techniques for further improvement is also in progress. 

Live vaccines are normally weakened strains that do not cause diseases in the host, but stiU can stimulate the immune response. A typical example is the poho vaccine. The weakening of microorganisms or attenuation of the vims or bacteria can be accompHshed by passage through different substrates and/or at different temperatures. Modem genetic engineering techniques can also be used to attenuate a vims or bacterium. 

In 1989, two enzymes based on genetic engineering techniques were introduced, ie, a cloned alkaline protease (IBIS) and a protein engineered Subtihsin Novo (Genencor, California). Lipase and ceUulase types of detergent enzymes have also begun to appear. 

A number of complex molecules such as proteins have been incorporated into the polyanhydrides, including insuhn, enzymes, chon-drogenic stimulating proteins, and a protein synthesized by genetic engineering techniques. 

While it is possible to use genetic engineering techniques to manipulate the sort of starch produced, at the time of writing the use of such starch in foods is illegal in Europe. The starch from genetically modified plants can, however, be used in industrial products such as adhesives. 

As discussed previously, murine antibodies have limitations. The next phase of development is to make these murine MAbs more like human antibodies, by using genetic engineering techniques. A recent approach is to humanize the antibodies to reduce HAMA and improve the avidity of the MAbs (avidity... 

Genetic engineering techniques have had a significant impact upon the research, development and commercialization phases of projects in the industrial enzyme business. The technology has proven successful and will play an even greater role in the future in expanding the present markets. 

Erythropoietin release is stimulated by hypoxia (low PO2). Within hours, the hormone ensures that erythrocyte precursor cells in the bone marrow are converted to erythrocytes, so that their numbers in the blood increase. Renal damage leads to reduced erythropoietin release, which in turn results in anemia. Forms of anemia with renal causes can now be successfully treated using erythropoietin produced by genetic engineering techniques. The hormone is also administered to dialysis patients. Among athletes and sports professionals, there have been repeated cases of erythropoietin being misused for doping purposes. 

While allelopathy is not covered in this chapter, excellent weed control can be achieved at reduced herbicide rate when used in conjunction with allelopathic rice varieties. Therefore, selection of highly allelopathic crop varieties, either through traditional breeding or using genetic engineering techniques, may also provide novel and low input approaches to weed control. 

Genetic engineering techniques to improve penicillin amidase yields during fermentation are now employed thereby reducing biocatalyst process costs. 

To increase the thermostability of existing enzymes by genetic engineering techniques is difficult, since molecular determinants that increase thermostability are hard to predict. Comparisons of heat labile and heat stable stmctures do however indicate that... 

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