TA: Malini Kotak
Abstract The experiment is conducted in order to identify a randomly given unknown gram-negative microorganism. By comparative analysis of biochemical tests that were performed throughout the semester to find out its characteristics and determine the identification of bacterium out of four potential unknown was given. To figure out the characteristics, T-streak was performed to isolate the sample from broth to a Tryptic Soy Agar plate, along with an additional slant in case something wrong with the original plate that can possibly affect the result. The gram-stain process of colonies then reveal its shape and morphology, using aseptic …show more content…
Also apply in food and medicine industry, research about the origin and relation between organism and so on. This study was conducted using techniques that have been learned so far in microbiology laboratory.
Organisms are divided into two domains: prokaryotes and eukaryotes, which further diverted in three other domains consists of Bacteria, Archaea and Eukarya , there are major different between these two where prokaryotes are much simpler internal structures, circular DNA, lack nucleus and any membrane bounded organelles and in general smaller in size. Bacteria and Archaea fall into this category, however despite they sharing same characteristics, Archaea are in fact closely relate to Eukarya than Bacteria. The domain bacteria is diverted with various prokaryotes, all pathogen fall under this category but not all bacteria are pathogenic (Madigan et.al …show more content…
MR test tube inoculated and incubated for 24 hours, ten to fifteen drops of methyl red indicator then added to the cultured. If it turned red then that was the positive for the presence of mixed acids. No color change was negative, however, if the media turned orange, it was inconclusive. VP test tube was inoculate and incubated up to 3 days, vortexed, added Barrits Reagent A (alpha-napthol) and Barrits Reagent B (potassium hydroxide). Red or pink color was positive reaction, no color change was negative, however it could take up to an hour to see the color change. SIM test then performed using inoculating needle in semi-solid media contains casein, amino acids, iron-contain compound and sulfur in form of sodium thiosulfate. Inoculated by stabbing technique and incubated for 24 hours, if the organism could reduce sulfur, a black color would be seen. To test for indole production, four or five drops of Kovak’s reagent was added into the cultured, a red color indicated a positive result. Last was to test for motility , if cloudiness was seen away from the stab line, then motility was