In the ever-evolving field of synthetic biology, achieving groundbreaking innovations goes beyond doing experiments in the lab. For our project, the impact is harnessed via interviews with experts from various fields, using this knowledge to reflect on decisions, identifying areas of improvements, and realizing these improvements into our project.

Project inspiration

Our project inspiration stems from the pressing global need for sustainable alternatives to conventional plastics. Microplastic pollution in the environment is an ever-increasing concern, with significant amounts of microplastics ending up in the food-chain1. Agricultural plastic waste, such as non-degradable fertilizer coatings, is a large contributor to this problem2. Recent studies have highlighted the alarming presence of microplastics in human blood and feces, as well as in embryos, raising health concerns3. In the face of this growing crisis, there is an urgent need for an effective solution. Our project aims to address this need by harnessing the potential of polyhydroxyalkanoates (PHA), biodegradable polymers produced by bacteria, to create eco-friendly alternatives that can mitigate plastic pollution and reduce our environmental footprint.


To ensure that our project aligns with societal needs and ethical standards, we contacted various stakeholders. Through these collaborative efforts, we have aimed to bridge the gap between scientific research and societal needs, ensuring that our project effectively tackles the real-world challenge of microplastics, while upholding the principles of sustainable innovation.

Expert fields

In the initial stages of our project, we conducted interviews with stakeholders that were crucial for transforming our initial idea to a concrete and viable project We classified our stakeholders in six different categories, all of which are sorted in chronological order.

    1. Identifying the problem
    In this category, we focused on identifying the problem of microplastic pollution in agriculture and the environment. Microplastics pose a significant threat to both food safety and ecosystem health. By understanding the extent of this issue and its implications, we gained insights into the urgency and importance of finding a sustainable solution Identifying the problem allowed us to set clear objectives for our project and establish its relevance in addressing this global concern.

    2. Finding a solution
    We recognized that the conventional use of petroleum-based plastics in agriculture was contributing to microplastic pollution. Therefore, we aimed to develop a viable alternative through the production of biodegradable plastic using genetically engineered bacteria. This category of stakeholders enabled us to explore various techniques and technologies to tackle the problem effectively, considering both the technical feasibility and environmental impact of our solution by interacting with many experts in these relevant scientific fields.

    3. Safety
    Safety was a big concern throughout our project development. To safeguard team members and the environment from potential risks associated with chemicals and equipment, we had to make sure that our extraction procedure was safe. To ensure that the use of PHA plastic in agriculture did not harm crops, soil, humans, or ecosystems, it was also crucial to evaluate the safety of the material itself. By prioritizing safety at every step, we aimed to deliver an innovative solution that not only addressed sustainability challenges but also upheld the highest standards of safety and environmental responsibility.

    4. Modeling
    Modeling played a crucial role in our project as it allowed us to predict and optimize the behavior of our engineered strains. By creating mathematical models, we could simulate the growth and PHA production of various mutants, aiding in the design and fine-tuning of our bioplastic production system in the lab. This category helped us bridge the gap between theory and experimentation, ensuring efficiency in our project.

    5. Extraction
    The extraction of PHA from bacterial cultures was a key technical aspect of our project. This category delved into the methods and techniques we used to extract and purify the biodegradable plastic efficiently. By interviewing (PHA) extraction experts we gained a lot of valuable knowledge which we were able to apply in the lab. Addressing extraction challenges, we aimed to make PHA production economically viable and environmentally friendly, further supporting its adoption in agriculture.

    6. Application
    The ultimate success of our project depends on its real-world application. In the application category, we explored how our biodegradable plastic could be integrated into agricultural practices to reduce microplastic pollution. Amongst others, we have talked to farmers, circular plastic experts, and regulatory organizations and discussed topics such as product durability, degradation rates, and compatibility with existing farming techniques. This category helped us envision the practical implementation and potential impact of our solution on agriculture, the environment, and public health.


Below you can find a compilation of the information we collected by talking to experts from the various fields, in an attempt to optimize our research and implementation process.

Follow our journey
Identifying the problem

Dr. Thijs Bosker

Professor working at the Institute of Environmental Science (CML) in Leiden

Key points that influenced our project:

  • Carry out toxicity tests and make a response curve to test the safety of your PHA product
  • Expertise on microplastics and the current status of the scientific field on microplastics
  • Advice on potential Life Cycle Assessment
  • Viability of bringing new PHA plastic to the market

Prof. Dr. Michael Richardson

Professor of evolutionary developmental zoology.

Key points that influenced our project:

  • We learned that nanoplastic size and how they enter cells via pinocytosis are crucial considerations for our project's design and for assessing environmental and health impacts
  • There is a high probability that nanoplastics influence human embryos because the embryonic development is highly preserved through evolution
  • Using biodegradable plastics for drug delivery is potentially challenging due to the body's inability to metabolize plastics and metals, making it crucial for any biodegradable system to degrade rapidly to avoid potential issues


RIVM - Rijksinstituut voor Volksgezondheid en Milieu (National Institute for Public Health and the Environment)

Key points that influenced our project:

  • Encouraged conversation on GMOs and the view of the public
  • Talked about the regulations behind the use of GMOs
  • Discussed forms of extraction

Prof. Dr. Anthony J. Sinskey

Professor of Microbiology at the Massachusetts Institute of Technology and expert in the field of biotechnology.

Key points that influenced our project:

  • We discussed the economics of biomanufacturing and the key factors of what makes a product viable
  • Indicated the key biological processes relevant to cost efficient production
  • Discussed the current and ideal forms of product extraction

  • Finding a solution

    Markus Buchhaupt

    The head of microbial biotechnology at the DACHEMA research institute

    Key points that influenced our project:

    • Provided recommendations for growing M. extorquens in a bioreactor, influencing our strain selection and methanol concentration experiments
    • Highlighted the necessity of an industry shift towards methanol as a feedstock to use methylotrophic bacteria

    Dr. Lennart Schada von Borzyskowski

    Assistant Professor at the Institute of Biology in Leiden.

    Key points that influenced our project:

    • Provided insight in the workings of different promoters and plasmids available for M. extorquens
    • Gave us recommendations for cloning strategies

    Dr. Nico Claassens

    Assistant Professor at the Institute of Biology in Leiden.

    Key points that influenced our project:

    • Methanol is considered a promising feedstock due to ease of storage and operation, but the cost of electricity, often the most expensive factor, must be taken into account
    • Hydrogen based PHA production requires a substantial investment and therefore methanol is a more feasible short-term option
    • He recommended optimizing PHA content through medium adjustments and genetic engineering

    Earl Goetheer

    Chief Technology Officer (CTO) at HighTech XL, an accelerator for deep-tech startups.

    Key points that influenced our project:

    • Provided insights on current prices of commercial methanol, including the differences between grey methanol and biogenic methanol
    • We learned that grey methanol performs poorly when applied to short-term usage, such as for PHA, but costly biogenic methanol is better from a sustainability point of view
    • Highlighted that PHA is interesting due to its circularity and that the price of PHA will reduce in the future

    Alberto Pettinau

    The head of R&D at Sotacarbo SpA, an R&D institute that works with the development of advanced low carbon energy conversion technologies.

    Key points that influenced our project:

    • Provided insights on the process of renewable methanol production
    • Advised us to compare our methanol production process to a more conventional one
    • Encouraged us to use methanol for feedstock for methylobacterium as the market for methanol production is growing

    Yvonne van Delft and Marija Sarić

    Work at the energy transition unit at TNO - Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (Dutch Organisation for Applied Scientific Research).

    Key points that influenced our project:

    • Insights on green methanol and bottlenecks in the production
    • Expertise on the difficulty of getting sustainable CO2 and the problem that gas and electricity prices are coupled in the Netherlands


    The Bio-Safety officers (BSO)

    The Bio-Safety officers (BSO) of the health, safety and environment (HSE) department of Leiden University, Faculty of Science, advised/helped us on the following aspects:

    • Gave us an instruction class on working with GMO's
    • Helped to perform a Risk assessment GMO
    • Determining which Risk Level laboratory to use
    • Helped us with implementing the Risk Assessment of Hazardous Substances tool


    Dr. Erika Tsingos

    Post-Doc at the Multiscale Mathematical Biology group of the Mathematics Institute of Leiden University, and now heads her own group at Utrecht University. She has extensive experience in the field of metabolic modeling.

    Key points that influenced our project:

    • She helped with setting up the analysis of the metabolic network model and gave suggestions on how to investigate the effect of various gene knockouts
    • She advised us on the experimental setup to validate the model predictions and how to compare the experimental results with the modeling results
    • She suggested the use of Flux Variability Analysis (FVA) as well as Flux Balance Analysis (FBA) to investigate reaction essentiality and identify potential knockout or upregulation targets


    Jonathan Salt-Waninge

    Expert on biobased and circular economy at Ecoras. He focuses on green chemistry, sustainable polymers and biobased solutions.

    Key points that influenced our project:

    • The extraction step is the production step that requires by far the most energy
    • Simplifying the production of PHA by eliminating the extraction step would reduce the production time frame and significantly decrease the need for solvents or other extraction methods
    • The drawback of this method is that biomass could introduce contamination in the form of non-thermoplastic elements, making the resulting PHA less pure, leading to inferior properties such as increased brittleness and reduced tensile strength

    Moritz Bross-Koch

    Team leader at an industrial biotechnological company called BASF.

    Key points that influenced our project:

    • He highlights that the extraction process for PHA/PHB is currently a significant challenge in the field
    • He suggests incorporating a washing step into the extraction process using either ethanol or acetate. This step could potentially improve the purity of the extracted PHA/PHB
    • He recommends optimizing the carbon flux towards the production of PHA/PHB, suggesting a focus on enhancing the production process rather than other aspects

    Jelmer Tamis

    Research and development engineer at Paques Biomaterials, a company that focuses on producing a natural alternative for plastic from wastewater streams.

    Key points that influenced our project:

    • He gave us advice on optimizing our PHA technique

    Application & Business

    Stéfan Ellenbroek

    The program director of Unlock_, the Life Science Incubator in Leiden.

    Key points that influenced our project:

    • Who to contact for larger investments
    • How to calculate the production price
    • Potentially invest in employees

    Marjolein Crooijmans

    PhD candidate at Leiden University's Faculty of Science.

    Key points that influenced our project:

    • How to structure a convincing business model
    • Key stakeholders and how to make a convincing business case
    • We must be aware of the current experiences our stakeholders are having with their products

    Rinco de Koeijer

    An agricultural farmer and previous president of local farmer union ZLTO from Aardenburg in the Dutch province of Zeeland.

    Key points that influenced our project:

    • Would buy PHA film if it was cheaper
    • Would buy PHA film if it was more expensive but had a lower carbon footprint and left no plastic remains on field
    • The plastic should ideally last for about one season
    • Consider irrigation (T-pipes) as an alternative application

    Dr. Anne Land-Zandstra

    Assistant professor at Leiden University's Faculty of Science.

    Key points that influenced our project:

    • How to structure a convincing business model
    • Key stakeholders and how to make a convincing business case
    • We must be aware of the current experiences our stakeholders are having with their products

    Karin Molenveld

    Programme manager renewable plastics at Wageningen BioBased Research.

    Key points that influenced our project:

    • Large-scale production facilities and volumes for PHA plastics have not yet become widely available in the market
    • Assessing the market potential of the entire PHA family is challenging due to its differences from fossil-based and other biobased materials
    • The application of PHAs in various markets has the potential to deliver substantial ecological improvements, aligning with environmental sustainability goals

    Dr. Soňa Kontárová & Dr. Přikryl Radek

    Researchers at the Brno University of Technology at the Faculty of Chemistry. With their team, they are involved in biopolymer research.

    Key points that influenced our project:

    • There is a need for alternatives in fertilizer coatings because of a new Fertilizing Products Regulation (FPR)7
    • The key advantage of using P3HB coating for fertilizers is that they can slow-release the nutrients of the fertilizer, reduce the dose required for the plant, and do not have a negative impact on the ecology in comparison to fertilizers with regular polymer coatings
    • When looking for a potential application of your PHA product, make sure that the biodegradable property of the polymer is actually demanded. It is the main selling point, but recyclability is meant as more necessary than biodegradability of bioplastic which is understood as unnecessary loss of material

    Thinagaran Letchimanan and Shaik Ling Ang

    Researchers at the Universiti Sains Malaysia in the School of Biological Sciences.

    Key points that influenced our project:

    • The majority of the fertilizers used are instant-release fertilizers. They provide adequate nutrients but a big portion is lost to the environment. Slow-release fertilizers seem to be a good solution to contain the nutrients and release the nutrients to meet plant demand
    • With a worldwide shift to a green economy and sustainable environment, using PHA as a green coating material to reduce plastic leaching into the environment is a feasible and impactful project
    • PHA-coated fertilizers have a good potential market. With improving technology in PHA production and recovery, the PHA cost will decrease, and PHA-coated fertilizers will become more profitable

    Jesse Hiemstra

    Senior account manager at Happy Cups, a Dutch company that produces PHA drinking cups.

    Key points that influenced our project:

    • Stressed the importance of focusing on high-end products as that market is better and people are willing to pay more for the product
    • Consider adopting a consumer-focused approach in your production strategy by minimizing intermediary involvement to reduce CO2 emissions. Opt for aluminium molds for their sustainability benefits, and ensure that the entire value chain benefits from your efforts
    • Emphasize the eco-friendliness of PHA products in your marketing efforts, as their attractiveness is strongly influenced by government policies favoring sustainability

    Esther van den Beuken

    Principal consultant of circular plastics at the TNO - Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (Dutch Organisation for Applied Scientific Research).

    Key points that influenced our project:

    • Addressing microplastics is challenging because even biodegradable materials may not always fully degrade due to suboptimal conditions, such as in water
    • Various types of bioplastics should not be mixed during collection, as doing so may compromise their specific properties during recycling
    • While the plastic in question may not be strictly circular in terms of recycling, it does exhibit circularity in terms of CO2, contributing to a carbon loop and achieving zero CO2 emissions

    Rob Verhagen

    The sustainability director & change agent for sustainable and circular packaging solutions at OPACKGROUP, a family owned packaging industry with 10 production locations in the Netherlands

    Key points that influenced our project:

    • Due to EU regulations banning single-use plastics, PHA may not be a suitable material for such applications
    • High-value applications might not be ideal for PHA because the expense of the product may not align with its relatively short lifespan
    • Determine the specific properties of PHA and adapt it to different products

    Prof. Dr. Han de Winde

    Professor in Industrial Biotechnology at Leiden University.

    Key points that influenced our project:

    • Even if plastic waste collection systems and conventional plastic degradation will be optimized, there will still be a big market for biodegradable plastics
    • In future experiments for strain optimization it is recommended to increase methanol resistance by directed evolution
    • To create (co)-polymers based on market demand, we can integrate enzymes of other microbes in the metabolism of M. extorquens to also allow for optimal co-polymer composition


    PHAse Out aims to optimize the bioproduction of PHA in M. extorquens to make biodegradable plastics. M. extorquens is advantageous as it naturally produces PHA, allowing us to focus our resources and time on engineering the bacteria to maximize PHA production. Since M. extorquens grows on methanol, this also removes the need to use sugars for PHA production, making our PHA production process environmentally and socially sustainable. Through our integrated human practices, we were able to create a holistic approach for addressing the fundamental problems relating to microplastic pollution, creating a greener and cleaner future for all.

    Identifying and understanding the problem, as emphasized in the expert interviews, is crucial for several key reasons.

      1. It ensures the safety and biodegradability of the PHA product, particularly in light of potential risks associated with nanoparticles and additives.

      2. It determines the market viability of the project, allowing the startup to take advantage of favorable opportunities.

      3. It allows for adherence to critical regulations and permits, particularly those related to GMOs and sector-specific requirements, ensuring legal compliance.

      4. It addresses public perception and concerns about GMOs, which can significantly impact the product's acceptance.

      5. It enables the strategic selection of target sectors for PHA applications, considering sector-specific regulations and requirements.

      6. It highlights the environmental implications, including the potential hazards of nanoplastics.

      7. Finally, it recognizes health considerations, particularly in medical applications, necessitating rigorous research to mitigate potential risks effectively. In summary, identifying and comprehending the problem is fundamental for the project's safety, market success, regulatory adherence, public acceptance, strategic sector targeting, environmental responsibility, and health risk mitigation.

    Firstly, it involves optimizing the growth conditions of M. extorquens for large-scale PHA production, with recommendations influencing strain selection and methanol concentration experiments. Secondly, it addresses the necessity of an industry shift towards methanol as a feedstock for methylotrophic bacteria like M. extorquens, potentially driving the adoption of these bacteria for PHA production. Furthermore, finding a solution entails selecting suitable promoters and plasmids for engineering M. extorquens, with insights aiding cloning strategies and gene expression optimization. Moreover, it involves understanding the economics of methanol production, as costs significantly impact the viability of using methanol as a feedstock for M. extorquens. Lastly, it encompasses addressing challenges in obtaining sustainable CO2 for methanol production and navigating the coupled gas and electricity prices in the Netherlands, both of which impact the feasibility of green methanol production.

    By shedding light on crucial aspects of PHA synthesis and extraction, the expertise and advice of the extraction experts had a significant impact on our project. Jonathan Salt-Waninge's insights emphasized the importance of focusing on PHA as a biodegradable plastic, and his suggestions about the extraction process led us to consider simpler and potentially more scalable methods. Moritz Bross-Koch's recommendations centered on optimizing the carbon flux toward PHA production, highlighting the relevance of metabolic engineering informed by computational predictions . Jelmer Tamis stressed the importance of cost-effectiveness and recommended direct extrusion as a preferable extraction approach, guiding our decision-making regarding extraction methods and material choices.

    The market potential of our PHA product was stressed by the application and business specialists, particularly in light of upcoming EU regulations. They also emphasized the significance of identifying suitable applications that are in line with PHA’s biodegradability. They highlighted the value of sustainability and circularity, pointing out that PHA can aid in lowering CO2 emissions, controlling microplastics, and minimizing environmental litter. In-depth market analysis, value chain integration, and utilizing government regulations were advocated by the experts as ways to boost sustainability. They underscored the necessity of raising consumer awareness about the eco-friendliness of PHA products and modifying PHA features for various applications. Overall, their insights guided our project's focus on sustainable agriculture applications and provided strategies for success in the PHA market.

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