Cell Disruption Essay

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1 Cell disruption Introduction Biological products synthesized by fermentation or cell culture are either intracellular or extracellular. Intracellular products either occur in a soluble form in the cytoplasm or are produced as inclusion bodies (fine particles deposited within the cells). Examples of intracellular products include recombinant insulin and recombinant growth factors. A large number of recombinant products form inclusion bodies in order to accumulate in larger quantities within the cells. In order to obtain intracellular products the cells first have to be disrupted to release these into a liquid medium before further separation can be carried out. Certain biological products have to be extracted from tissues, an example being porcine insulin which is obtained from pig pancreas. In order to obtain such a tissue-derived substance, the source tissue first needs to be homogenized or ground into a cellular suspension and the cells are then subjected to cell disruption to release the product into a solution. In the manufacturing process for intracellular products, the cells are usually first separated from the culture liquid medium. This is done in order to reduce the amount of impurity: particularly secreted extracellular substances and unutilized media components. In many cases the cell suspensions are thickened or concentrated by microfiltration or centrifugation in order to reduce the process volume. Cells Different types of cell need to be disrupted in the bio-industry: • Gram positive bacterial cells • Gram negative bacterial cells • Yeast cell • Mould cells • Cultured mammalian cells • Cultured plant cells • Ground tissue Fig. 4.1 shows the barriers present in a gram positive bacteria. The main barrier is the cell wall which is composed of peptidoglycan, teichoic acid and polysaccharides and is about 0.02 to 0.04 microns
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