May plastic-free

This month we participate in the Flemish initiative mei plasticvrij (May plastic-free). By using less single-use plastic for a month, more awareness is created about the plastic problem. This problem already starts with its production. Fossil fuels are used in a polluting process, which is accompanied by the emission of a significant amount of greenhouse gases. And in the end, plastics too often end up in the environment, polluting our waters with microplastic. On the other hand, thanks to their versatile properties, plastics can hardly be excluded from our daily lives. For example, they are the ideal packaging material for certain food products, providing better protection and longer shelf life.

That is why the search for more sustainable plastics is on the rise. Our research focuses on polyhydroxyalkanoates (PHA). PHA are bioplastics in every aspect: produced from biomass, in a biological way and fully biodegradable. In fact, they are made by naturally occurring bacteria. These microorganisms can accumulate the polymer intracellularly up to 80% of their weight. Hence, by cultivating them in a bioreactor and feeding them with biomass, such as plant sugars and oils, we can efficiently and sustainably produce large quantities of PHA. So why don't we find these natural bioplastics everywhere in the supermarket? Unfortunately, the current production process is still too expensive and thus not competitive with traditional fossil-based plastics. This is largely due to the cost of the biomass. In addition, also the cultivation of this biomass is controversial, as it competes with the cultivation of food and feed crops.

So what if we could use a different feedstock? Suppose we start from a carbon source that we are desperate to get rid of: carbon dioxide (CO2). Indeed, in our research, we focus on the production of bioplastics from CO2. Besides PHA-producing bacteria, also CO2-consuming bacteria are present in nature. The latter thus use CO2 as a carbon source and can utilize hydrogen (H2) as an energy source. From this gas mixture, they produce acetic acid, a molecule that can be used as a substrate by the PHB-producing bacteria. Conclusively, we can produce bioplastics via an ingenious two-step fermentative process and also fix CO2. It is obvious that the latter also benefits our environment. For example, this process could be applied to capture CO2 emissions from a factory. The emissions would then no longer end up in the atmosphere and be converted into valuable bioplastics - a double win.

With the expertise of both (UGent) and Bio Base Europe Pilot Plant (Ghent, Belgium), and the financial support of FWO, I can work on this concept in my doctoral research. It includes the development of an innovative two-step fermentation platform where we study the potential of different microbial strains and look for the optimal conditions for both processes and their coupling. Ultimately, via these CO2-derived bioplastics, we aim to get another step closer to a sustainable bio-economy.

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