Team:TU Darmstadt/Applied Design

Applied Design

The Problem

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

These chemicals are mainly used for the production of plastic, digital devices, clothes and tires[2]. According to the International Energy Agency (IEA), petrochemicals will be the largest driver of oil demand in the future[3]. But with all the oil extraction come high environmental costs. The extraction 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, cracks might reach up to the ground water and contaminate it [4]. This results in not only harming the people living in these areas, but also the local ecosystems. Since the demand for petrochemicals produced from cheap oil or natural gas increases, there is a significant increase in the construction of petrochemical factories. Even during the production of petrochemicals, these factories emit massive amounts of greenhouse gases. In comparison, a coal plant running at full capacity twenty-four hours, seven days a week will release about 4.6 million tons of carbon dioxide a year, while a petrochemical factory in Louisiana, USA, emits 9 million tons of greenhouse gases per year[5]. 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 thereby raise 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, USA, is endangered by severe storms [6]. Over the past decades, there were several catastrophes with oil spills, that leaked from fractured factories and had a major negative impact on the local sea life. This is why a factory like the one near New Castle is not only endangering itself, but is also a high risk for its environment.

The Solution

All the above mentioned problems make it clear, that there is a great need for an alternative to petrochemicals. As reported by the Center for International Environmental Law [7], more than 99% of plastic is produced using petrochemicals. This is why we want to particularly challenge the plastic production. In our project, 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, lactic acid (to form PLGA) and caprolactone (to form PLGC together with glycolic acid and lactic acid). To ensure „green“ monomer manufacturing, we engineered the glyoxylate cycle of Escherichia coli and Saccharomyces cerevisiae. With this alternative, we hope to minimize the dependence on petrochemicals, thereby reducing the demand for petrochemicals and indirectly decreasing the need for oil and natural gas extraction. This way, we hope to further the 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 [1], we achieved to produce our monomers in E. coli and S. cerevisiae. In addition, our chemistry group successfully produced PLGA and PLGC. We also created an example application, the nanospheres. These find a rising demand as drug delivery systems because of their harmless degradation in the human body and their ability to constantly release medicine. This unharmful degradation is called biodegradability and is a major benefit for our project. According to the Cambridge Dictionary, a biodegradable substance is able to decay naturally and without harming the environment [8]. This differentiates us from many other plastics, for example the slow degradable polystyrenes or PET.

Another advantage is, that we do not have to use solvents during the polymerization. In some cases, there is a need to use cancerous and toxic fluids to solve the monomers before the reaction. In our case, there is no such need to use solvents, because we polymerize directly in the monomer melt.

Local and Global Impact of our Project

As mentioned before, we managed to produce an environmentally friendly and sustainable synbio way to produce polymers. Throughout the process, we managed to avoid many toxic substances and provide useful alternatives. But how does this affect our lives and environment? Referring to the Environmental Integrity Project, in the USA alone, there was an expected greenhouse gas production from petrochemical factories of 86 million tons in 2015 [5].Since these gases cause global warming that impacts all of humanity, a decrease in the demand for petrochemicals could lead to less petrochemical factories and therefore a lower greenhouse gas emission. Moreover, with reducing the interest in petrochemicals, the demand for oil and natural gas decreases as well. This leads to a lower risk of accidents with oil refineries at seashore or with fracking, polluting the ground water on land or endangering sea life through oil spills. Furthermore, in not using toxic solvents for our polymerization, we lower the risk of chemical leakage and potential catastrophes during their transport. So, there is also a positive impact on the local environment and ecosystem in not risking any chemical contamination.


We are aware that there is still a high need for alternatives to petrochemicals and that our project is just the beginning, but we are looking forward to a world of green thinking and innovation, in which we reduce pollution, regenerate the environment and provide a healthy future for humanity.

References

  1. ↑ AFPM Petrochemicals, 10/14/2018 [2].
  2. ↑ Petrochemical application, 10/14/2018 [3].
  3. ↑ IEAs info page for petrochemicals, 10/14/2018 [4].
  4. ↑ The future of natural gas, MIT, 10/14/18 [5].
  5. ↑ 5.0 5.1 Environmental Integrity Project, 10/14/2018 [6].
  6. ↑ Newspaper article grist, 10/14/18 [7].
  7. ↑ Center for International Environmental Law, 10/14/2018 [8].
  8. ↑ Cambridge dictionary, 10/14/18 [9].