Lab #2: Media Prep and Autoclave, Plate Pouring

Introduction

Cultured media, in a lab setting, assistance scientist in congregating a better understanding of the vast assortment of bacteria and their behavior.  Understanding how and why we do this is critical in striving for awareness and prevention of harmful entities. The route which allows us to promote these bacteria, in a lab setting, is called, media. Media is a nutrient rich broth that provides a nurturing setting for bacteria to cultivate.  Fortunately, our lab was more focused on practicing the art of pouring media than the method behind making media.

Methods and Materials

For this lab, our professor premade the intended media, Luria-Bertani (LB) and R2A, due to this process being lengthy and time consuming. Once she showed us the process behind constructing the media, she let us loose on trying to implicate the correct process of plate pouring; pouring media into a sterile petri dish. It was imperative to expose the media and sterile petri dish to as little contamination as possible; breathing on the media, surrounding air. When pouring the media, one should only pour enough media to cover approximately eighty percent of the bottom of the petri dish. Close the lid, then gently swirl so the media may spread and coat the bottom of the dish. Each student poured four to five dishes in order to gain experience in the correct lab procedure.

Figure 1:Sterile sleeve of petri dishes

Figure 2: Beaker of LB

Figure 3: 6 poured plates

     

Figure 4: 1 poured plate

Results

                There were no results in this lab. These plates are to be used for future labs.

Discussion

                In this lab students used two different types of media, LB and R2A. Both are commonly used media’s but LB grows bacteria at a much quicker rate than R2A. R2A is ideal for mixed cultures and LB for pure cultures.  The reason for making both of these media’s was for student to gain insight for each.  Also, perhaps in the future labs we will need different media for different cultivation samples.

                Though there are different types of media, the process behind making them in very similar and neutral. Media is just a nutrient rich surface for bacteria to grow, and bacteria are very temperamental. When trying to grow pure bacteria cultures, the pH should remain neutral to be complacent.  

                My group’s plates were not uniform which encourages the mantra of practice makes perfect. I think that we all took the understanding of, pouring your plates so eighty percent was covered, very differently. I thought that was in regards to the bottom of the plate while other group members saw it as pouring the petri dish up eighty percent.  But whichever way we each poured our plates we were consistent.