Identifying Two Unknown Microbes From A Mixed Culture

Introduction
The purpose of this unknown lab is to separate and identify two unknown microbes from a mixed culture. Kathryn Bart define a mixed culture as "one that contains more than one type of organism growing in a sterile medium, such as agar. The mixed culture can include multiple species of viruses, bacteria and parasites, which may or may not live in harmony with one another, sharing the available resources" (Kathryn Barr, 2016). I took number five test tube from the different microbes that I had the option of choosing from. From that I created a mixed culture for myself and was able to do a gram stain to narrow down my unknown microbes. A mixed culture contains many species that disperse into colonies after been placed in the incubator …show more content…
Usually to start a lab you would create a streak plate on a mixed culture to see if it would grow under ideal temperatures. From this you can create a gram stain. If you see purple gram stain that indicates that it’s a positive gram stain and that the bacteria is present. If you look under the microscope and you notice a pink stain that means that its a negative gram stain and that the bacteria is not present. Isolation technique is a method that allows you to isolate colonies of an organisms on an agar plate. The purpose of this technique is that it allows you to isolate microbes in order to identify what type of bacteria it is. The biochemical tests are quick and easy way to identify bacteria because it reduces the number of possible species present very quickly. Some of the biochemical tests that are in the tube are Phenol Red Dextrose, Phenol Red Lactose, Phenol Red Sucrose, and Simmons Citrate. If the color of the tubes change than that is an indicator of the presence of bacteria. Another type of biochemical test is the EMB, Starch, and Mannitol Salt. On the starch plate you need to put some iodine on that which will indicate if the bacteria is there. If you notice a halo zone then that means that the bacteria is …show more content…
My hypothesis was supported because I was able to use the five I’s of microbiology to narrow down my two unknown microbes. My first unknown which is the yellowish one was rod shaped however on the table that was provided states that the yellow microbe should have a coccus or tetrad shape. This was hard to identify because it grew at slower pace than my second microbe. The EMB plate was a negative for my test however, once compared to the table from other students it states that it should have a purple growth. I believe the first microbe is Kocuria rhizophila since the color and my other biochemical tests also confirmed to have the same results. My second Unknown bacteria is a cloudy white pigment. Once I examined the gram stain it showed that it was a positive and that the arrangement was cluster like and when I compared that to the unknown bacteria data table it showed that both the shapes and arrangements match. That helped me to narrow it down drastically since it was the only one that was shaped like the way it was. My biochemical tests matched perfectly with Enterobacter aerogenes. One huge experimental error I made was not doing the gram staining correct the first time but I tried to fix it. I had to redo my nutrient agar plates twice because the first time it seemed like there was only one microbe. It was hard to isolate the microbes