<buttontype="button"class="collapsible"><imgclass="button_pic"src="https://static.igem.wiki/teams/4378/wiki/img/terminator-glasses.png">Visit to Uppsala Vatten</button>
<buttontype="button"class="collapsible"><imgclass="button_pic"src="https://static.igem.wiki/teams/4378/wiki/img/terminator-glasses.png">Visit to Uppsala Vatten Biogas Facility</button>
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<h3>Visit to Uppsala Vatten Biogas Facility</h3>
<p>Aim: Learn about bioreactors within the Uppsala waste-management system. Learn more about plastic recycling.
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It was a warm and sunny Monday, the last week of June, when we set out to visit Uppsala Vatten and their biogas facility at Kungsängen. We were met by Stina Bengtsson, who gave us a short introduction to the methane-producing bioreactors they have. In short, Uppsala Vatten collects organic waste from Uppsala municipality and several others, grinds and boils it to finally feed it to methane-producing bacteria. The natural gas is collected and methane is concentrated from it, while the remaining organic waste-slurry is used as fertiliser for local farmers. We were then given a tour of the facility and its machines, followed by a short lecture on plastic waste management. Stina gave us some names of people we could contact in order to get a better understanding of how these bioreactors were designed, so that we could use that knowledge in order to understand how our system could possibly be designed in the future if successful.</p>
<li>These bioreactors worked as a tiny eco-system. Based on bacteria from manure, different types of organic waste have been added and the bacterial flora has been formed over time. We wondered if they had a “starter culture”, or if they sometimes had to supplement with bacteria when production was slow, but the starter culture from the manure provided at the start and the constant adding of new “feed” meant that the bacterial flora was very stable.</li>
<li>We also asked about external factors, such as temperature, pH-levels, moisture, and oxygen levels. They do keep the reactors isolated so they have a very low oxygen level, which is crucial to the bacteria forming methane rather than carbon dioxide. However, besides this, they did not affect temperature (for example cooling in the summer heat or warming during winter), pH-levels nor moisture levels. It truly worked as an ecosystem achieving homeostasis.</li>
<li>We were also curious about possible contaminations. It is well known that organic waste can contain E. coli, Listeria and Salmonella, but the boiling of the organic waste in 70°C for an hour was done to prevent contamination. They have never had problems with unfavourable bacteria growing within their bioreactors. </li>
<li>Another topic of discussion was if their bacteria was engineered in some way, or if they would like them to. Their system uses naturally occurring bacteria that have not been genetically engineered in a lab. This is great, since any leakage of bacteria would not be harmful.</li>
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<p>Regarding our project, we would advise the following for designing a bioreactor that could possibly feed a PET slurry to engineered bacteria and extract useful chemicals such as PCA:</p>
<li>It’s always best to use non-GMO in case of leakage, or to design the GMO so that it will die when it is moved outside of the bioreactor. There are several strategies for this already established, but for our system it would mean that another set of genes would have to be inserted in addition to the PET-degrading genes.</li>
<li>The plastic would have to be treated before entering the bioreactor so that it would not contaminate it. Heat would be an option, especially since heat would start the process of loosening the PET-molecules from each other and making it easier for the degrading enzymes to access the PET-chains.</li>
<li>As opposed to the slurry fed to the bacteria of Uppsala vatten, the E. coli would get a PET slurry. Would the culture need supplements? Monitoring oxygen levels and pH would be smart, but how would the bioreactor need to be designed so that for example oxygen could be pumped in? Bioreactors used for pharmaceutical production are large compared to our lab bench systems, but a bioreactor able to take care of plastic waste from a smaller city would need to be of a significantly larger size. It would, no doubt, take a lot of talented engineers to design such a system for keeping GMO happy and the world outside safe from any leakage.</li>
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<p>* pictures *</p>
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<h3>Visit to Uppsala Vatten Biogas Facility</h3>
<p>Aim: Learn about bioreactors within the Uppsala waste-management system. Learn more about plastic recycling.
