{"id":1213,"date":"2014-10-14T18:58:39","date_gmt":"2014-10-14T18:58:39","guid":{"rendered":"http:\/\/www.lifeandnews.com\/articles\/?p=1213"},"modified":"2016-08-30T23:52:21","modified_gmt":"2016-08-30T23:52:21","slug":"how-we-tricked-e-coli-bacteria-into-making-renewable-propane","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/how-we-tricked-e-coli-bacteria-into-making-renewable-propane\/","title":{"rendered":"How we tricked E. coli bacteria into making renewable propane"},"content":{"rendered":"<p>By <a href=\"http:\/\/theconversation.com\/profiles\/patrik-jones-136904\">Patrik Jones<\/a><em>, Imperial College London<\/em><\/p>\n<p>Converting renewable energy into electricity is one thing; converting it into fuel is quite another. The vast majority of global energy demand is for fuel, and a renewable source could help us heat our houses and travel efficiently long into the future. It might even mean we could avoid the conflicts that will arise while competing for the last remaining fossil fuels.<\/p>\n<p>Today, we are a step further towards this goal after engineering the gut bacteria <em>E. coli<\/em>, most famous for the strain of it that <a href=\"https:\/\/theconversation.com\/supershedding-cows-could-be-the-biggest-cause-of-e-coli-25301\">causes food poisoning<\/a>, to make it generate renewable propane. My colleagues and I detail our work in a study published in the journal <a href=\"http:\/\/dx.doi.org\/10.1038\/NCOMMS5731\">Nature Communications<\/a>.<\/p>\n<p>Scientific advances now mean we can make microbes churn out useful energy, by changing the way they process energy. These microbes can then convert the \u201crenewable\u201d sunlight (and carbon dioxide) into fuel, either directly or using sugar as an intermediate stop-over.<\/p>\n<h2>Why propane?<\/h2>\n<p>Although the technology for renewable conversion of solar energy into electricity already works well, this isn\u2019t quite the same as being \u201crenewable energy\u201d. Approximately 85% of total energy demand is actually for fuels, as it is far easier to store energy in fuel rather than as electricity.<\/p>\n<p>Industrial scale production of cheap renewable fuel therefore runs into a big problem. It needs to out-compete fossil fuels \u2013 an alternative technology that only needs to pump out the ready product.<\/p>\n<p>In searching for a renewable fuel process that could be economically sustainable we focused on propane, a bulk component of liquid petroleum gas. Propane is an attractive target for several reasons.<\/p>\n<p>It\u2019s a gas, which means you could immediately separate the finished product. The microbes who produced the propane would be left behind and the new fuel will escape as a gas. No need for a messy separation.<\/p>\n<p>That said, propane also requires little energy to liquefy, thereby enabling the high-energy density storage that is required for cost-effective usage. There\u2019s a reason your car\u2019s gas tank is actually full of liquid \u2013 gas simply takes up too much room.<\/p>\n<p>The fact propane is already in commercial use also helps. It\u2019s used as a fuel in rural areas or in industry, and sometimes also for transport. In Italy, for example, thousands of stations sell propane-containing mixtures under the label \u201cAutogas\u201d.<\/p>\n<h2>Making renewable propane<\/h2>\n<p>You can\u2019t make renewable propane through natural reactions \u2013 no organisms naturally pump out propane in the way humans breathe out CO<sub>2<\/sub> or trees exhale oxygen. We therefore turned to synthetic biology, where biology meets engineering, in order to create such a capability.<\/p>\n<figure class=\"align-centre\"><img src=\"https:\/\/62e528761d0685343e1c-f3d1b99a743ffa4142d9d7f1978d9686.ssl.cf2.rackcdn.com\/files\/58031\/width668\/95f722py-1409667838.jpg\" alt=\"\" \/><figcaption><span class=\"caption\">The friendly bacteria?<\/span><br \/>\n<span class=\"attribution\"><span class=\"source\">US Department of Health<\/span><\/span><\/figcaption><\/figure>\n<p>We chose <em>E. coli<\/em> because it is easy to engineer. Left to its own devices, <em>E. coli<\/em> takes glucose from its surroundings and breaks it down into smaller carbon molecules, electrons and \u201cinternal\u201d chemical energy. These smaller parts are used only as building blocks for cellular growth \u2013 to reproduce.<\/p>\n<p>In the engineered cells, however, we hijack the assembly line for one of those building blocks known as \u201cfatty acid synthesis\u201d. Fatty acids are normally synthesised mainly in order to generate cell membranes but, by introducing a special enzyme, we can redirect it to instead release butyric acid, the precursor for propane.<\/p>\n<p>From there, only two <a href=\"http:\/\/www.pnas.org\/content\/110\/1\/87\">more enzymes<\/a> were needed in order to <a href=\"http:\/\/www.sciencemag.org\/content\/329\/5991\/559\">convert this smelly fatty acid into propane<\/a>. All in all, this was achieved by introducing only five genes \u2014 a very, very tiny fraction of the more than 4,000 genes present in the entire genome of <em>E. coli<\/em>.<\/p>\n<p>Our work represents a proof-of-concept for renewable fuel development as we deliberately selected a process that considers all steps of the pathway from production to utilisation. All in order to maximise chances of commercial production.<\/p>\n<p>At the end of the day, that is what is most important \u2013 to enable sustainable and renewable conversion of sunlight and CO<sub>2<\/sub> into fuel, with minimal impact on the environment.<\/p>\n<p><img loading=\"lazy\" src=\"https:\/\/counter.theconversation.edu.au\/content\/31209\/count.gif\" alt=\"The Conversation\" width=\"1\" height=\"1\" \/><\/p>\n<p><em>This work was supported by the European Research Council under the European Union\u2019s Seventh Framework Programme (FP7\/2007-2013)\/European Research Council Grant Agreement 260661 (P.R.J.).<\/em><\/p>\n<p>This article was originally published on <a href=\"http:\/\/theconversation.com\">The Conversation<\/a>.<br \/>\nRead the <a href=\"http:\/\/theconversation.com\/how-we-tricked-e-coli-bacteria-into-making-renewable-propane-31209\">original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>By Patrik Jones, Imperial College London Converting renewable energy into electricity is one thing; converting it into fuel is quite another. The vast majority of global energy demand is for fuel, and a renewable source could help us heat our houses and travel efficiently long into the future. It might even mean we could avoid [&hellip;]<\/p>\n","protected":false},"author":39,"featured_media":7564,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[118],"tags":[],"_links":{"self":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/1213"}],"collection":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/users\/39"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/comments?post=1213"}],"version-history":[{"count":2,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/1213\/revisions"}],"predecessor-version":[{"id":7565,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/1213\/revisions\/7565"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media\/7564"}],"wp:attachment":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media?parent=1213"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/categories?post=1213"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/tags?post=1213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}