Team:Estonia_TUIT - 2020.igem.org

Implementation

Introduction

While planning the project, it is important to consider the real-life implementation of the developed product or method. Our team decided to design, build and test both genetically modified yeast strain for lipid production as well as a bioreactor prototype. Together, these two components form a fully functional system for light-driven lipid production. Our prototype could be further upscaled for industry use.

Biotech companies

We envision that companies may use our developed strain as a platform to produce a variety of high-value lipid-derived products used in medicine, cosmetics, food industry, etc. The strain has several advantages:

Light-inducible overexpression of TAGs synthesizing enzymes to improve lipids final yield
Light-inducible overexpression of lipid droplet structure protein to promote stabilization of TAGs in lipid droplets
Inactivation of the oxidative portion of pentose phosphate pathway (PPP) to allow higher carbon flux towards lipid biosynthesis
Separate growth and production phases to further economize the production process
Introduced cell self-lysing mechanism to minimize extraction and purification costs

Public opinion

Our team thought thoroughly about our project main goal. We believe that our project will provide a cleaner and more sustainable solution for manufacturing lipid-derived products in GM yeast.

To make sure our project approach is accepted by the general audience (our potential customers) we conducted a survey. The results showed that people consider GM organism bioproduction methods as a good alternative to conventional production. Furthermore, it is important for them that the products they consume leave minimal environmental footprint. (More info about the survey could be found on the Human Practices page)

Hence, our project would not only meet the expectations of the potential consumers but also provides the possible solution to the industry.

Yeast-InP biohybrid

The use of indium phosphide (InP) nanoparticles in our design provides both advantages and disadvantages. On the one hand, harvesting light with nanoparticles to provide electrons for NADPH formation is beneficial, since light is one of the cleanest energy sources.
However, the current nanoparticles themself are not ideal. InP presents potential health risk to people occupationally exposed to its dust. Because of this, several independent organizations (IARC, REACH, AGS, and BMAS) have concluded that InP is a hazardous substance, and it is listed on the 2017 list of Critical Raw Materials for the EU because of possible risks of supply shortage. These facts may negatively affect our project but with the help of prof. Guo we found that InP nanoparticles are at the moment the most sustainable, green, and least toxic semiconductor for biohybrid engineering. Moreover, prof. Guo stated that InP nanoparticles may be recycled. Together, this expert’s opinion greatly increases the value of our project since it means the production could be fairy easily upscaled.

Bioreactor prototype

To provide ideal conditions for our constructed yeast our team decided to build a bioreactor. Several aspects of project design needed to be taken into account while engineering the bioreactor:

During the growth phase, light-inducible promoters must stay inactivated while InP nanoparticles need to be illuminated to supply cells with sufficient amount of electrons for NADPH synthesis;
Growth temperature should be held constantly at 30 °C;
The cells should be constantly mixed to provide equal illumination and supplementation throughout the culture.