Difference between revisions of "Team:Austin UTexas/Demonstrate"

Kombucha Strains

• Successfully isolated microbes from various samples of kombucha.
• Identified strains of bacteria and yeast using rRNA gene sequencing.
• Characterized each of the isolated microbes to facilitate further experimentation.

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Results

Conjugation

• Attempted conjugation with G. oxydans.
• Performed minimum inhibitory concentration experiments between G. oxydans and spectinomycin, carbenicillin and kanamycin.
• Determined that G. oxydans is resistant to spectinomycin and carbenicillin.

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Recapitulation

• In a process called "recapitulation," we successfully created a kombucha-like culture by adding individual strains of microbes instead of a living culture containing the entire kombucha microbiome.
• Determined that the microbe Ga. hansenii is essential for the fermentation of kombucha.
• Determined that two distinct strains of the yeast Lachancea fermentati are necessary for the fermentation of kombucha, including one that appears to produce high quantities of C02.

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Ethanol

• Found literature describing sequences for genes involved in the metabolism of ethanol to acetic acid in the bacterium Ga. hansenii.
• Designed Golden Gate parts for the assembly of these genes into a functional construct.
• Used a bromothymol blue assay to compare changes in pH resulting from fermentation in multiple strains of Lachancea fermentati isolated from our kombucha.

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Brazzein

One of the potential methods to create designer kombucha is to add a brazzein gene into the bacterial strains. Brazzein, a protein found in the pulp of the edible fruit of the African plant Pentadiplandra brazzeana Baill, is an extremely sweet substance¹. It is 2,000 times sweeter than sucrose by weight. This makes it a healthy and economical alternative to sugar. Commercial production of brazzein is limited, however, because it comes from a tropical plant. If it could be more easily harvested, it could be used to improve the flavor of various foods and drinks, including kombucha. By genetically engineering the brazzein gene into the bacteria in kombucha, the drink could be sweetened without adding sugar or excessive calories. While still being a GMO product, this beverage would be low in sugar and could appeal to a health-conscious consumer.

References

1. Yan, Sen et al. “Expression of Plant Sweet Protein Brazzein in the Milk of Transgenic Mice.” Ed. Xiao-Jiang Li. PLoS ONE 8.10 (2013): e76769.
2. Brazzein protein structure acquired from European Bioinformatics Institute

pH Sensors

• Successfully created a neutral pH sensor with a reporter.
• Further characterized the P-atp2 Biobrick.
• Found literature describing three putative promoters in Gluconobacter oxydans that increase transcription under acidic conditions, and currently characterizing these sequences.

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