Spring Sequencing Analysis & Final Project

 Spring Sequencing Analysis

We finally got the Spring 2021 sequencing data back! Yay! Since we did not get the data back as early as originally anticipated, we did a Unique Microbe Analysis on last semester's data then formulated a hypothesis we could test with this semester's data. If you have not seen it yet, I would recommend that you read my Unique Microbe Analysis blog post first for information on the specific microbe I researched. 

Spring Sourdough Starter Samples

I analyzed samples 87 and 89 from the Spring sourdough starter samples. Sample number 87 was a control starter and sample number 89 was an experimental starter containing apple. These two samples were grown and submitted by the same individual. 

My unique microbe, Gluconobacter oxydans, was found in both samples. Not only did I find this microbe in samples 87 and 89, but I also found it in sample 88, which was another experimental starter from the same individual. This starter contained mango. There was a higher percentage of G. oxydans in the apple starter than the control starter, but there was an even higher percentage in the mango starter. This was surprising to me since I did not find that G. oxydans has ever been closely associated with mangos. 

These bars show the percentage of G. oxydans in each sourdough starter sample.
It is easy to see that there was a larger percentage in the mango starter than the apple
or control starter. It may be more difficult to visually determine the difference between
 the apple and control starter, but there is a higher percentage in the apple starter than
the control starter. The apple starter was 0.133% G. oxydans while the control
starter was 0.081%.


Testing My Hypothesis 

This result did not support my hypothesis. After analyzing the data from last semester, I was expecting to find G. oxydans in sourdough starters containing apples, grapes, and peaches. I also wondered if this microbe would be found in starters that smelled like vinegar since G. oxydans is a type of acetic acid bacteria. 

Although G. oxydans was found in a starter containing apple, it was also present in the control starter, as well as the individual's other fruit starter containing mango. This suggests that the presence of G. oxydans in the sourdough starters is not a result of the type of fruit present since there was no fruit in the control starter that also contained the microbe. With this microbe being found in all three starters from this same individual, I began to wonder if some environmental factor(s) could have come into play. 

Gluconobacter oxydans and Sourdough Production

After analyzing the Fall 2020 and Spring 2021 sequencing data, we were asked whether we thought our microbe of interest was beneficial, detrimental, or neither for sourdough production. Based on the observations I made during my analyses, G. oxydans does not appear to be very beneficial or detrimental to sourdough production. Although I found in my research that this microbe has been associated with sourdough, I only observed very small percentages of G. oxydans in a few samples I looked at. It was not present at all in most samples. 

Continuing the Experiment

If I was going to continue working with these preserved samples, I think I would first want to try answering my original research question. Then I would like to continue looking further into the unique microbe that I chose. I would like to compare the percentage of G. oxydans in different starters and look at their observed phenotypes to try to determine if this microbe could potentially increase sourdough growth. With those results, I would like to try to determine which genes are responsible for the increase or inhibition of growth associated with the microbe. 

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Final Project 

For my final project, I created a podcast to share the story of my sourdoughs and the results of our research project with the general public. Personally, I am not really a fan of podcasts so I did not think I would like making one, but once I got the hang of it, it was actually pretty fun. I might actually start following other podcasts and listening to them now. 

I originally created a single episode for the draft of final project. When I revised this, I divided it up into five separate episodes. To listen to my podcast, Sourdough Science with Sav, you may use this link. Each episode has links to blog posts and transcripts in their descriptions. Below, I will provide a link to each individual episode that I published for the revised version of my podcast. 

Final Project Episode # 1: My Sourdough Starters 

Final Project Episode # 2: Apples & Applesauce 

Final Project Episode # 3: Rising Rate Experiment

Final Project Episode # 4: DNA Sequencing & Research Questions

Final Project Episode # 5: Unique Microbe Analysis & Final Results


I enjoyed making this podcast to share our findings with the general public, and I hope you enjoy listening! As this semester comes to an end and I publish my last blog post and podcast episode, I hope that I have inspired at least one of my viewers or listeners to begin their own sourdough starters. 

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