Background

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Petrochemicals and artificially-synthesized acids are responsible for the manufacturing of everyday items including personal care products, pharmaceutical formulations, food additives, industrial solvents, and bioplastics. A more environmentally-friendly approach that remains economically competitive with nonrenewable petroleum is needed with growing concerns over global warming. While extensive research has been done on utilizing microalgae for biofuel production, methods available constrain its prospects as a source for future energy. The commercial production of biofuel is not yet economically viable due to slow rates of production from microalgae. The metabolic engineering of the heterotrophic yeast Saccharomyces cerevisiae, which can be grown anaerobically, using a cost-effective wastewater-based growth medium could potentially provide a solution. Manipulation of the fatty acid biosynthesis pathway is key to inducing the production of fatty alcohols that can act as direct replacements to standard petrochemicals.

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Purpose

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The purpose of this study is to metabolically engineer Saccharomyces cerevisiae for enhanced fatty alcohol and free carboxylic acid production while utilizing wastewater as a cost-effective nutrient culture source. Fatty alcohols can be used as effective replacements for petrochemicals for the production of a host of items, including pharmaceutical formulations, food additives, plastics, polymers, detergents, lubricants, and shampoos. A wastewater-based medium would provide organic material for the yeast to utilize to grow that would be more cost-effective than standard media on a large scale. In addition, it would also allow for the degradation of harmful organic content in the wastewater, aiding in the wastewater treatment process.

 

Hypotheses

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• If the ACC1 (encoding a deregulated acetyl-CoA carboxylase), FAS and the mFAR1 (mus musculus) genes are overexpressed in S. cerevisiae, then fatty acid, fatty alcohol, and ethanol accumulation will result.

• If human wastewater (mixed liquor) is utilized as a carbon source after sterilization and nutrient balance, then yeast cell viability will persist in wastewater media, and organics in the media will be degraded.