Tryptic Soy Agar Lab Report

Scientists use different types of nutrient agar media to help with the study of microorganisms. The purpose of this experiment was to examine the different growths of minority organisms within a variety of media cultures. These cultures included types of selective, differential, and enriched media and were applied to split sections on the agar plate. Each of the four broth cultures: Escherichia coli, Enterobacter aerogenes, Staphylococcus epidermidis, and Streptococcus faecalis showed observable growth when applied. The different medias will either promote or inhibit the growth of the organisms allowing their isolation to be possible (Lengeler and Schlegel, 1999). These four types of organisms will react accordingly based on their preferable environmental conditions. Observing their growth …show more content…
In table 1, three of the organisms: E. coli, E. aerogenes, and S. epidermidis, had abundant growth while S. faecalis had moderate growth. All samples corresponded to the ideal results as seen in table 4. Since tryptic soy agar is a type of enriched media, it has an extra abundance of nutrients causing microorganisms to colonize. In tryptic soy agar, some ingredients include: pancreatic digest of casein, papaic digest of soybean meal, and sodium chloride (Reddy et al., 2007). The casein and soybean meal present in this nutrient plate provides a source of organic nitrogen, vitamins and minerals, such as amino acids and peptides with longer chains (Siegrist, n.d.). As well, the soybean meal also has sugars, further promoting the growth of bacteria (Siegrist, n.d.). Lastly, the sodium chloride in this plate helps sustain the osmotic equilibrium. Through these extra components on the tryptic soy agar plate that are not present in the other plates, the microorganisms are in a more preferred environment. Because of this, there is more growth observed for all four organisms than on the EMB plate or the KF streptococcal