From 2013.igem.org

Revision as of 16:40, 12 September 2013

ELECTROBACTER : from used frying oil to electricity

Project description

Have you ever tasted those delicious French-fries from your favorite fast food restaurant or even at home watching that nice movie? Or have you lately ate some grilled/fried hamburger meat, fried fish or nuggets?…Humm, ok you might think I’m just hungry and this is nothing to do with an iGEM project, right? Totally wrong! Yes… we are talking about a Synthetic Biology project and is all about our daily life, better saying it’s about our daily waste, and not to mention, one of the most environment contaminating wastes: used frying oil. It is produced in deep-fried food preparations mainly in bars, restaurants, industrial kitchens, hotels and even in our own homes, and its production has tremendously increased over the last years. We are disposing approximately 146 million tons of used frying oil per year. However, do you know the final destination of it? Well, many (yes many) people (I mean 90% of the population) still doesn’t know, and even worse: we do not know what to do with the frying residual oil and ending up discarding it without any pre-treatment, therefore, polluting rivers, lakes, oceans and soils, killing all sorts of living organisms and messing up ecosystems. Some actions have been done since much time ago trying to remove or treat this kind of waste, such as making soap or more recently taking this frying oil residue and turn into biofuel. Great options but still very timid when we think the amount of used frying oil production every year (and scaling up), and the need of to be rid of this waste. The equation for the environmental contamination by residual oils is like that: up to one million liters of water for each liter of oil! Looking at this huge humanity problem we came with a SynBio project for this year’s iGEM competition. We saw a great potential in using Synthetic Biology for tackling not just the used frying oil waste but on top of that turn this waste electric energy. Yeap, you read that right! To be more precisely, an electric power plant will be set into bacterias. The high demand of electric energy, the shortage of fuels and search for renewable energy sources, and the rise of Synthetic Biology sets up a great opportunity for doing so. Aiming to provide an alternative to the reuse of this disposed oil we started “The Electrobacter” project, a bacteria capable of degrade used frying oil and turn it into electric power. Soon, the destiny of waste fats for energy generation will have a new bio-energy alternative through a Bioplant.

The Gram-negative and protobacteria Shewanella, is a spread genus included in Amazon River. It has the capacity of degrade fat acids with different chain sizes as carbon sources, through β-oxidation, due to enzymatic reactions. The expression of these enzymes is regulated by the product of the FadR gene. We are going to use a new chassi in iGEM and build new biobricks based on both: the Registry and the Amazonian biodiversity. We are modifying the metabolic expression of some key components in order to increase fat degradation using of course used-frying-oil. Shewanella bacterias also releases electrons to the media and from there we are able to “capture” it for electric energy production. For this, we´ll do:1) inhibition of the codifying gene of β-oxidation repressor protein (FadR), making it “hungrier” for fat acids; 2) the increasing FadL expression, responsible for the entrance of fat acids in the cell; and 3) high expression of FadD, responsible for the insertion of CoA in the fat acid. For the conversion of chemical energy into electric energy, the Shewanella naturally transfers electrons produced during the β-oxidation. In order to “capture” it we are building a MFC (Microbial Fuel cell), which is a device capable of generating electricity through electrons transfer to an internal circuit. In the near future homes and restaurants will be relying on electric power generated by waste oil used to make French fries...by a bacteria...awesome, wouldn't be?