1.0 The liquid agar harden at around 42

1.0 Introduction 1.1-media preparation Cultivation of microbes is a method of multiplying microorganisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested, or both.

Any medium for development of microbes must give certain essential dietary prerequisites, which incorporate a carbon source that may likewise fill in as a vitality source, water,a nitrogen source, a phosphate source and different mineral supplements, for example, iron and magnesium.Broth medium is a liquid medium without agar, that contains tryptone, yeast powder and other ingredients and components that basically break down in the water. The agar (a complex carbohydrate extracted from marine algae) is a cementing operator for microbiology media. When the agar is adding into broth medium cause the medium to be solidify. The agar medium is selected because it is not a nutritional component by to provide nutrient to the vast majority of the bacteria and have higher melting point (90-100 °C).

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The liquid agar harden at around 42 °C.Slants agar are created by bringing agar to the boiling point and pouring it into a test tube. Before the agar cools and solidifies, the test tube is set on its side. Once the agar is cooled, the test tube can be stored upright, and the agar inside has a slanted appearance.. Agar plate are created by bringing agar to the boiling point and pouring it into a petri dish. Before the agar cools and solidifies, the petri dish set on its side.

Complex media usually contain complex materials of biological origin such as blood or milk or yeast extract or beef extract ,  the exact chemical composition of which is obviously undetermined. Complex media usually provide the full range of growth factors that may be required by an organism so they may be more handily used to cultivate unknown bacteria or bacteria whose nutritional requirement are complex. Complex media are usually used for cultivation of bacterial pathogens and other fastidious bacteria.

 Defined media are usually composed of pure biochemicals off the shelf. A defined medium is a minimal medium provides only the exact nutrients (including any growth factors) needed by the organism for growth. The use of defined minimal media requires the investigator to know the exact nutritional requirements of the organisms in question. Sterility is defined as an absolute term that means the absence of all viable forms of life. Sterilization is the process of achieving sterility. In practice sterility is achieved by exposure of the object to be sterilized to chemical or physical agent for a specified time.

Aseptic technique means using practices and procedures to prevent contamination from pathogens. It involves applying the strictest rules to minimize the risk of infection. Autoclaving is the sterilization by  steam at a pressure about 15 psi; attaining temperature (121oC) will kill all organisms and their endospores in about 15 minutes. The sterilization occurs by three mechanisms: temperature, pressure, and thermal oxidation.

Starting values of pH 7.2–7.4 for an medium is ideal to nearly all the cells because with the too acidic or too alkaline medium that will affect the cell cultures to grow. Agar is suitable for using in this media because of good clarity, controlled gelation temperature, controlled melting temperature, good diffusion characteristics, absence of toxic bacterial inhibitors and relative absence of metabolically useful minerals and compounds.1.2 Growing of microbesThe purpose to grow the microbes in-vitro (in the lab) is to obtaining the pure cultures . it is importance of having a pure culture, and not a mixed culture, when performing biochemical testing is that a pure culture may react much differently in isolation than when it is combined with other species.

Bacteria replicates at infinitesimally long rates and one species may enforce or weaken the other. The method which is used to obtain the pure cultures are serial dilution method and spread plat method ..ConclusionWe are able to get 1.59×105 cells(colony-forming units) per millilitre of original sample from a serial dilution.


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