Team:TU Darmstadt/Applied Design

combimer

• Home
• People
  • Team
  • Collaborations
  • Sponsoring
  • Attributions
• Project
  • Background
  • Monomers
  • Glycolic Acid Production in E. coli
  • Glycolic Acid Production in S. cerevisiae
  • Caprolactone Production in E. coli
  • Polymers
  • Analytical Background
  • PLGA
  • PLGC
  • Applications
  • Upscaling
  • Notebook
• Achievements
  • InterLab
  • Parts
  • Proof of Concept
  • Applied Design
• Modeling
• Human Practices
  • Human Practices
  • Education & Engagement
• Safety

The problem

Think of petrochemicals as specific chemical compounds, which can be manufactured from oil, natural gas, coal or other sources. However, the majority of petrochemicals are derived from oil or natural gas. [1]

These chemicals are mainly used for the production of plastic, digital devices, clothes and tires. [ https://outreach.afpm.org/Petrochemicals/why-petrochemicals-matter-to-you-2.html] According to the International Energy Agency (IEA) petrochemicals will be the largest driver of oil demand in the future. [2] But with all the extracting of oil there comes high environmentally costs. The extracting of natural gas on land can be done via hydraulic fracking methods. Fracking is a highly used method, in which rock is split up with pressurized liquids. Since the fracturing of the rock is not controllable, it can happen that cracks reach up to the ground water and contaminate it. This results in not only harming the people living in these areas, but also the local ecosystems. Since the demand on petrochemicals produced by cheap oil or natural gas increases, there is a big rise in building petrochemical factories. Although, during the production, these factories produce massive amounts of greenhouse gases. In comparison, a coal plant running at full capacity around the clock will release about 4.6 million tons of carbon dioxide a year, while a petrochemical factory in Louisiana emits 9 million tons of greenhouse gases per year. [3] All this pollution of the atmosphere leads to smog and acid rain. Additionally, the greenhouse gases warm up the earth, melting the polar caps and rising water levels. The rise of the water level then endangers oil refineries, which are built at a certain level above the water, but cannot change their initial height. As an example, an oil refinery near New Castle is endangered by severe storms [4]. Over the past decades, there were some catastrophes with oil spills, that leaked from fractured factories and hat major impact on the local sea life. This is why it factories like the one near New Castle is not only endangered by itself, but is also a high risk for its environment.

The solution

To sum up all the above, there is a great need for an alternative to petrochemicals. As reported by the Center for international environmental law, more than 99% of plastic is produced using petrochemicals. This is why, we want to particularly challenge the plastic production, to change the reliability on petrochemicals and thereby reduce the demand of producing these chemicals and indirectly decreasing the need of oil and natural gas extraction. In Detail, we chose to provide a sustainable, environmentally friendly synthesis of PLGA and PLGC. These polymers are not only biodegradable, but also useful for a wide field of applications, such as drug delivery systems, prosthetic implants or cosmetic products. They consist of three monomers: glycolic acid and lactic acid (to form PLGA) and caprolactone (to form PLGC together with glycolic acid and lactic acid). To ensure the green monomer manufacturing, we engineered the glyoxylate cycle of Escherichia coli and Saccharomyces cerevisiae. With this alternative to petrochemicals we hope, to make it possible to meet climate, air quality and water pollution goals in the future.

The Highlights of our project

As you can see from our proof of concept subpage, we achieved to produce our monomers via E. coli and S. cerevisiae. In Addition, our chemistry group successfully produced PLGA and PLGC. We also manufactured an example application, the nanospheres. These find a rising demand as drug delivery systems because of their unharmful degradation in the human body and its ability to constantly release medicine. This unharmful degradation is called biodegradability and is a big benefit of our project. According to the Cambridge Dictionary a biodegradable substance is able to decay naturally and without harming the environment [5]. This property sets us apart from many other plastics, for example the slow degradable Polystyrene or PET.

Another great thing is that we do not have to use solvents during the polymerization. In some cases, there is a need to solve the monomers before the reaction with cancerous and toxic fluids. In our case, there is no such need to use solvents, just because we polymerize out of the melt. This means the physical state of our monomers at the reaction start must not be fluid but solid.

Making an impact

As mentioned before, we managed to produce an environmentally friendly and sustainable synbio way to produce polymers. Throughout the manufacturing, it was managed to avoid many toxic substances and provide useful alternatives. But how does this effect our lives and environments? Referring to the Environmental Integrity Project, just in the USA there was an expected greenhouse gas production from petrochemical factories of 86 million tons in 2015 [6]. Since these gases cause global warming that impacts all of humanity, a reduce in the demand of petrochemicals could lead to less petrochemical factories and therefore a lower greenhouse gas emission.