Team:NYU New York/Description
New York University
Project Description
Inspiration
Flavonoids are a diverse group of plant metabolites that are naturally found in fruits, vegetables, and other plants. They are known to exhibit a wide range of human health-related benefits, including anti-oxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. The myriad of benefits that flavonoids could provide makes them applicable to many industries: nutraceuticals, pharmaceuticals, medicine, cosmetics, and even the dyes/textiles industry.
As a team, NYU iGEM researched possible applications of flavonoids and how they are conventionally obtained. It turns out, flavonoids are naturally found at low concentrations in plants and require extraction and isolation methods that can be costly and result in low yields. We saw this as a problem that could be solved with synthetic biology. However, numerous groups have already succeeded in producing flavonoids at high titer, using a paradigm known as metabolic engineering. Metabolic engineering involves modifying various metabolic pathways in cells to direct molecular flux toward a desired target. By controlling the flow of molecules from a substrate to a product, metabolic engineers can control and optimize for higher yields of various molecules, including flavonoids. NYU iGEM decided to build on the work of metabolic engineers by exploring a method by which genetic circuits could be controlled more exactly and efficiently: optogenetics.
Optogenetics has been used in the past several years as a new way to signal cells with light. However, until recently, the fields of optogenetics and metabolic engineering had not crossed. However, metabolic engineering is inefficient as of now due to its reliance on chemical inducers to turn on gene expression. Chemical inducers, when introduced into any production-scale reactor, are far from evenly dispersed. This creates a heterogeneous activation of target genes and lowers yield. Light, however, has the capacity to penetrate a medium more evenly and thus be absorbed with greater efficiency. Light can also be turned on and off instantly, whereas chemical signals may need to be washed out of media, an inefficient and costly process especially at the industrial scale. Thus, optogenetic stimulation may be a good future modality for metabolic engineering at both the lab and the plant scale.
During our process of selecting which flavonoid to create using our synthetic biology method, we noticed that all flavonoids were similar in structure, therefore making it relatively simple to convert one into another. We realized that we could use a modular system of production to create flavonoids and optimize our process so that the highest possible titers were produced.
The Problem
Current methods of flavonoid extraction are costly, time-consuming, and wasteful. Plants are notoriously slow growers. A lavender plant can take up to 200 days to reach maturity, while roses can take several weeks to bloom. During this time of growth, plants require sunlight, water, and nutrients. If plants are being grown in an environment that they are not native to, specific temperatures and humidity levels must be provided by humans to allow for adequate growing conditions.
However, even after a plant has reached full maturity, methods of extraction and isolation can still be costly and inefficient.
Our Solution
By engineering E. coli to be able to produce flavonoids, we can reduce the time needed for synthesis and simultaneously increase yields over what could naturally be obtained by plant extraction. We utilized genes that could respond to light (optogenetic genes) to activate or repress certain genes for a period of time to increase conversion rate between different flavonoids. In order to accomplish the goal of being able to increase production of the flavonoids, we also created a fully-functioning bioreactor that could grow the cells and activate them using green light.