Phyiscal and chemical control of growth and viabilty Essay - 1

Phyiscal and chemical control of growth and viabilty - Essay Example Environmental requirements are particularly physical conditions that affect the amount and type of microbial growth. For example, activities of enzymes are dependent on environmental temperature. Microorganisms are also classified into groups based on their preferred environmental temperature. For example: thermophilic organisms, thermophiles prefer very high temperatures of above 400; mesophilic organisms, mesophiles grow well in temperatures of 200 to 400; while psychrophiles, psychrophilic organisms prefer relatively low temperatures. However, a range of maximum or minimum growth temperature exists for every individual species. The best growth occurs at optimum growth temperature (Singh, 2010). Another environmental requirement for microbial growth is the extent of alkalinity or acidity of the habitat, also referred to as a pH solution. Most of the microorganisms prefer an optimum pH of between 6.5 and 7.5. The tissues of the human body is between 7.0 and 7.2, therefore neutrophilic microorganisms often grow in the body very well. Other microorganisms such as those in yoghut and sauerkraut which are acidophilic grow well in acidic environment of below 6.0, for example yeast and molds. Microbial growth also does well where osmotic pressure is idyllic. In most cases, the concentration of salt in microbial cytoplasm is around one percent. Where there is one percent concentration of salt in the environment, the osmotic pressure is at optimum. In case the salt concentration rise in the external environment, water will definitely flow out of the cytoplasm through osmosis via cell membrane to the environment resulting into shrinking of the microorganism, and ultimately death. In contrary, where external water has minimal salt, water flows into the cytoplasm through the cell membrane resulting into cell swelling and ultimately burst. Conclusively, microorganisms living in