IDENTIFICATION OF CITROBACTER FREUNDII THROUGH BIOCHEMICAL TESTS.Jebin JacobNovember 15, 14Naghmeh HassanzadehUnknown - 10PurposeThe purpose of this study is to identify an unknown bacterium from a mixed culture, conducting several biochemical tests. Bacteria are an integral part of our ecosystem. They can be found everywhere and identifying them becomes fundamental to understanding their characteristics and effects on other living beings, especially humans. Biochemical tests help us identify the microorganism present with great precision. The tests used in this experiment are rudimentary but represent a fundamental starting point for tests used in medical laboratories and help students better understand how tests are conducted in a real laboratory environment. The first step in this process is to use the Gram stain technique to narrow down unknown bacteria into one of two large domains; Gram-negative and Gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are elimination processes that rely on the ability of bacteria to break down certain types of food sources, their respiratory capabilities, and other naturally occurring biochemical conditions. The results of these tests demonstrate that the unknown organism is Citrobacter freundii referred to here as C. C. freundii belongs to the Enterobacteriaceae family, like all the other unknowns reported in this test. The species is facultatively anaerobic and is a gram-negative bacillus. C. freundii is a motile, non-spore forming, rod-shaped bacterium with a typical length of 1-5 μm. The seven biochemical tests conducted to narrow down gram-negative staining are Phe...... paper medium......which identifies unknown bacteria and their implications for humans and nature. ReferencesPang, A., Warren, M.J. and Pickersgill, R.W. (2011), Structure of PduT, a trimeric bacterial microcompartment protein with a 4Fe–4S cluster binding site. Acta Crystallographica D, 67: 91–96. doi:10.1107/S0907444910050201Whalen JG, Mully TW, English JC. Spontaneous Citrobacter freundii infection in an immunocompetent patient. Arco Dermatolo. 2007;143(1):124–125.Puchenkova, S.G. (1996). "Enterobacteria in water areas along the Crimean coast". Mikrobiolohichnyi zhurnal (Kiev, Ukraine: 1993) 58 (2): 3–7Wang, J.T.; Chang, South Carolina; Chen, Y.C.; Luh, K. T. (2000). "Comparison of antimicrobial susceptibility of Citrobacter freundii isolates at two different time periods". Journal of Microbiology, Immunology and Infections = Wei mian yu gan ran za zhi 33 (4): 258–262.