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Nobody had ever seen microbes or even thought they might exist because microbial effects could be explained in other ways.

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Microbes. Nobody had ever seen microbes or even thought they might exist because microbial effects could be explained in other ways. What we now call biotechnology probably began as a kind of magic 1000's of years ago. It took a huge leap into turning into a science in the 1670s when a Dutch microscope maker called Anton van Leeuwenhoek looked at a sample of his own saliva. Factors that affect the growth of microbes are called limiting factors and influence the growth of cells in culture: - nutrient availability, temperature, pH, oxygen and build up of toxic material. An unfavourable level of any one of these factors can slow them to slow down or stop growth. Commercial Biotechnology. The commercial production of microorganisms used to be by batch culture - a culture was set up and after a period of growth it was harvested. A more recent method that has been used to grow the organisms in continuous culture - along-term operation over many weeks, during which time nutrient medium is added as fast as it is used and the overflow is harvested. Biotechnology is the use of biological agents to produce or process some other material. ...read more.


Selecting a strain. Enzymes are only produced by living cells and microorganisms are used to produce enzymes on an industrial scale. The scope for detecting new and useful organisms is huge. E.g. 10's of millions of microorganisms of many different types exist in a gram of soil. Less than 1% of the world's microorganisms have been researched so there is much more scope for research. Strain selection is necessary to find the microorganisms that will produce an enzyme that will do exactly what is required. Strains must therefore not make humans ill; some could be genetically altered. Organisms that are selected to produce the enzymes that are used in the food industry have to comply with very strict rules and regulations. The responsibility of the final product's safety lies with the product manufacturer. Intracellular and Extracellular enzymes. The enzymes are always produced inside the cells but many pass out through the cell walls into the growth medium. These are known as extracellular enzymes. Enzymes that stay within the cell are known as intracellular enzymes. Most of the enzymes that are used in industrial applications are extracellular enzymes produced by microorganisms during fermentation; the process can be either using a submerged or a surface culture. ...read more.


contact with protein that it can break down into amino acids for the bacterium to absorb - so each bacterium is producing more enzyme in order to maximize the harvest of amino acids from the small amount of protein that is available. If the organisms are given too little nutrients then they will not survive at all. The biotechnologists provide a medium that contains just sufficient nutrient to ensure that the microorganisms in the main fermenter produce the maximum amount of enzyme and continue to grow without increasing the number of cells. This stage of population growth is called the exponential growth phase and it is the production phase of the fermentation. It is also important to control the other growth factors e.g. oxygen level, pH and temperature are also monitored and controlled. Maximum enzyme production is achieved when each of the growth conditions is maintained at its optimum. Enzyme production is more efficient today than 100 years ago as: - * Genetic manipulation of microorganisms has improved yields; * Low-cost nutrients and advanced monitoring have improved fermentation technology; * New methods extract a greater proportion of the enzymes from the cell; * Down stream processing techniques are more efficient; * Continuous production in special reactors is more efficient than batch processes. ...read more.

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