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Isolation of a urea degrading bacteria.

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Introduction

Michael Plit 3021034 Isolation of a Urea Degrading Bacteria Introduction Urea was the first organic chemical to be synthetically produced^1,^ previously it was thought that only living creatures could produce organic compounds Urea is naturally produced by the kidneys as waste from the degradation of amino acids. It is because of this that urea is commonly found in soils and is a useful nutrient source for bacteria that are able to utilise it, such as, Helicobacter pylori, Klebsiella pneumonia, all species of Proteus and Micrococcus luteus. These bacteria degrade urea in a reaction catalysed by the urease enzyme, CO(NH[2])[2 ]+ H[2]O �CO[2] + 2NH[3.] this process benefits the bacteria in several ways. The bacteria use the ammonia that is produced for respiration, the products also raise the pH of the environment. This promotes the growth of many urea degrading bacteria and inhibits competition from many other bacterial species. ...read more.

Middle

the chance of urea degrading bacteria being present was increased. * Culture in nutrient broth. This allowed all isolated microbes to grow. * Plate sample onto urea plates. On these plates urea was the only nutrient available, this meant that any bacteria that grew could degrade urea. * Perform urease test. Isolated bacteria are grown in a broth containing phosphate buffer, yeast extract, 2% urea and phenol red. An agar slope of the medium is heavily inoculated and incubated at 37^0c for at least four hours. If the organism only has low urease activity the phosphate buffer will neutralise the NH[3] produced. A red colour indicates that NH[3] has been produced and the result is positive^5.^ * Perform Gram stain. This is the most important stain in bacteriology and differentiates between gram positive and gram-negative cell walls, which indicates many things about cell structure, and taxonomy. ...read more.

Conclusion

luteus Results Test Result Urease Positive Gram Stain Positive Cocci Catalase Positive Motility Non-Motile Hugh and Leifson Obligate Aerobe These tests show that the isolated bacteria are Micrococcus able to degrade urea. Discussion The ability to degrade urea is no longer of great benefit to any species of Micrococcus although it remains a useful method of distinguishing M. luteus from other species. However, this is not the only test developed for this purpose. Before its revision based on 16s RNA, the Micrococcus genus contained nine species. M. luteus was separated from other species based on the following biochemical tests and their results^9. Test Result Citrate Negative Lactose Peptone Water Negative Glucose Peptone Water Negative Growth on 7% Na + NaCl Positive These tests are now redundant. If analysis of 16s RNA is not done, M. luteus can be distinguished on sight from other Micrococcus as it is now the only yellow species. References 1.smallfry.dmu.ac.uk/chem./mom/urea/urea.html 2. bergeys 2001 3. chinese Antarctic micrococcus 4 textbook 5.microbial methods pg 54 6.46 7.42 8.37 9.bergeys 1994 [1]http://www.britannica. ...read more.

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