P4SB – From Plastic waste to Plastic value using Pseudomonas putida Synthetic Biology | P4SB | Project | News & Multimedia | H2020 | CORDIS

Periodic Reporting for period 3 - P4SB (P4SB – From Plastic waste to Plastic value using Pseudomonas putida Synthetic Biology)

Periodo di rendicontazione: 2018-04-01 al 2019-03-31

350 million tons of plastic were produced in 2016 alone, with Europe accounting for ~60 million tons/year. The environmental impact of these primarily oil-based plastics, specifically PET and PU, has been broadly discussed. The use of PET for packaging, especially in the beverage industry, has contributed significantly to reducing energy expenditure during transport. However, recycled PET is of lower quality and current recycling techniques are barely competitive, leading to an overall European PET recycling rate of less than 30%. PU (polyurethane), on the other hand, is used extensively in a wide range of applications including construction, transportation, furniture, and medicine. Since many PU types have a thermoset nature (not meltable), one of the main concerns for this product is the notable lack of end-of-life recycling, with recycling rates below 5%. This ultimately leads to an increased plastic pollution of natural habitats, including our oceans.
In order to counteract these problems, the revised EU Waste Framework Directive has set a minimum plastic recycling target of 50% for household waste and 70% for building and construction waste, which must be reached by all EU Member States by 2020. The European Union emphasizes this efficient use of waste in the Focus Area “Waste: a resource to recycle, reuse and recover raw materials.” However, without a clear technology roadmap – let alone an appealing market strategy, this increase in recycling rates will not be achievable. On this background, P4SB proposes the engineering of a new-to-nature of biotechnological route to recycle PET and PU waste to added value bio-products. For PET, we specifically target the lowest quality post-consumer products that are not amenable to traditional recycling methods. When successful, PET and PU waste can be established as novel second generation carbon sources for biobased plastics. Thus, through Synthetic Biology, P4SB will enable new value chains across sectors including materials, chemicals, and environmental technologies within the framework of a sustainable knowledge-based bio-economy that will ultimately be to the benefit of the economy, environment, and society.

We aim to achieve the sustainable and environmentally friendly bioconversion of crude oil-based plastic waste into fully biodegradable bioplastics. This concept of plastic up-cycling will be proven through four major parallel research lines (see figure).

1. Plastic depolymerisation
Although plastics are generally considered to be very recalcitrant in nature, there are microbes and enzymes that can degrade them. We have identified PET and PU degrading enzymes and characterized their activity. We have engineered the enzymes themselves towards a greater activity, stability and efficiency, and we have also optimized the process in which these enzymes are applied to degrade plastic waste.

2. Monomer metabolism
The enzymatic depolymerization of plastic leads to plastic monomers such as terephthalate and ethylene glycol. We have engineered our bacterial P4SB workhorse Pseudomonas putida, convincing it to eat all of the monomers that result from the depolymerisation from PET and PU, and use them for growth.

3. PHA production
Polyhydroxyalkanoates (PHA) are carbon storage polymers of Pseudomonas. In other words, they are the equivalent of our fatty tissue. PHA is a biodegradable bioplastic that is excellently suited for applications in, e.g. adhesives and films. We have identified conditions in which Pseudomonas ‘gets fat’ from plastic monomers, and have also convinced the bacteria to produce new types of PHA and PHA-derived chemicals.

4. PHA secretion
An efficient PHA production process substantially relies on an efficient way to get the product out of the bacterial cells. We have developed several concepts to make this process more efficient, and have started to test these concepts on our bacteria. These parallel activities must have been brought together into a complete process. In order to do this efficiently, we developed new synthetic biology tools to more effectively engineer our bacteria, and we made and used computer-based models of our enzymes, bacteria, and processes, in order to understand and predict our results.
Due to P4SB, PET is now considered a carbon source for plastic manufacturing, while patents are covering the IP. The novel enzyme activities allow hydrolysation intensification, while the consolidated bacteria allow plastic monomer up-cycling to polyesters etc. Research findings are followed up by partners raising funding from national and international institutions.
We were and are also actively communicating with the scientific community, but also with a broader audience in magazines, on the radio and even on TV. P4SB (www.p4sb.eu) is a member of the EU Ocean Plastics Lab (https://oceanplasticslab.net) will be highlighted by KETBIO (www.ketbio.eu) and will be presented at the World Expo 2020 in Dubai. The P4SB project is being coordinated by RWTH.

P4SB is progressing towards the realization of the novel value chain from low-grade plastic waste to high value bioplastic. We named three visible social impacts that will emerge in the long run from P4SB. The main driver for increasing recycling rates of PET and PU is an economic incentive that we see in the production of bioplastic and therefrom derived products. With such an incentive in place, the collection rate will improve, but even more importantly the recycling rate will increase.
After four years, the P4SB consortium achieved significant progresses beyond the state-of-the-art in single technologies. Examples are the up-scaled depolymerisation of PET at increased temperatures and the production of PHA from depolymerized PET plastics and the discovering of enzymes able to degrade urethane chemical bonds. The achieved consolidation of technologies gives truly novel options for the recycling industry. So far the main socio-economic impact is on the consortium partners who develop new knowledge, experience, and technology.
The academic partners supervised more than 30 bachelor and master theses that were dealing with aspects of P4SB. Besides the technical training, the students involved achieved a solid understanding of the plastic recycling challenges the EU, and countries worldwide, face. Educating the next generation of biotechnologist, synthetic biologist, and bioprocess engineers will help to implement novel value chains as envisaged in P4SB, but also in the upcoming bioeconomy. For world-wide education P4SB is presented in a Multi Open Online Course (MOOC) on the envisaged sustainable bioeconomy that is covering many aspects of bioplastics (can be found on edX - www.edx.org).
The outreach, especially via the web, but also via traditional media formats like newspaper and TV, helps to inform the public about the challenges around plastic waste and the novel approach we are developing. A large volume of scientific papers have been published as a result from the project, including several joint consortium publications, and contributions from individual partners in high-ranking journals such as Science and Nature Communications.
In summary, the continuous progress of P4SB is attracting a lot of scientific, public, and industrial attention. The first actual demonstrations of the entire bio-upcycling workflow from plastic waste to new value-added products have now been generated, and will soon be made public.

Conceptual overview of P4SB – From Plastic waste to Plastic value using Pseudomonas putida

P4SB – From Plastic waste to Plastic value using Pseudomonas putida Synthetic Biology

Periodic Reporting for period 3 - P4SB (P4SB – From Plastic waste to Plastic value using Pseudomonas putida Synthetic Biology)

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