To differentiate between bacteria, fungi and yeast, we plant four different microbes in plates under the same environment for one week and compare the growth of the four microbes by macroscopic and microscopic observation. Meanwhile, the diversity of bacteria and fungi in humans, the environment and wood could be observed. In addition, the four substrates are cultured in two media, MEA and NA, under the same condition. Thus, how nutrients affect the growth of bacteria and fungi could be achieved. During the experiment, the sterile technique takes a significant role and should be well known and performed by students.
Material and Method
MEA (malt extract agar)
NA (nutrient agar)
Laminar flow hood
Substrates: mushroom, bad fruit, decay wood, soil, and other surface like human skin
In the first stage of culturing media, 8.33g Oxoid MEA and 7.5g NA are weighed out and suspended separately in two media bottles with 500ml distilled water. The media bottles are loosely capped and sterilized by autoclave at 121C for 15 min before removed for cooling to 55C. Then, each mixture in these two bottles is poured into two Petri dishes under sterile conditions. The dishes are cooled and solidified overnight. The next stage, examination of microbes in the environment, is to take a swab of a random surface of the four substrates and place it on both NA and MEA plates. Each plate is halved by a marker to plant two organisms. After labeling the plates, the four plates are placed for incubation at 23C for micro and macro observation.
MEA: large gelatinous cover in yellow in half of the plate
NA: yellow paint covering one sixth of the plate with several white spots
MEA: gelatinous cover in yellow in a small part of the plate along with a dark brown spot in the center NA: gelatinous cover in brown in...