{"id":110233,"date":"2022-06-02T07:04:00","date_gmt":"2022-06-02T05:04:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=110233"},"modified":"2022-05-30T12:16:54","modified_gmt":"2022-05-30T10:16:54","slug":"research-team-advances-biological-alternative-to-producing-common-petrochemical","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/research-team-advances-biological-alternative-to-producing-common-petrochemical\/","title":{"rendered":"Research Team Advances Biological Alternative to Producing Common Petrochemical"},"content":{"rendered":"\n\n\n

For decades engineers have dreamed of programming organisms to sustainably produce ethylene, a chemical that is nicknamed \u201cthe king of petrochemicals\u201d for its importance in plastics. Now, one hopeful pathway to this petrochemical is nearing reality, via a photosynthetic bacterium that is genetically specialized to turn sunlight and carbon dioxide (CO2<\/sub>) into ethylene. But before industry can load up on tanks of living green liquid, researchers are first overcoming some metabolic barriers around ethylene production.<\/strong><\/p>\n\n\n\n

\"Liquid
Liquid cyanobacteria culture is grown in Jianping Yu’s lab at NREL to advance sustainable ethylene production. Photo by Dennis Schroeder \u00a9<\/strong> NREL<\/figcaption><\/figure><\/div>\n\n\n\n

A cross-institution research team led by the National Renewable Energy Laboratory (NREL) made important progress toward deciphering the photosynthetic enzyme pathway. In a Nature Communications<\/em> article titled \u201cA guanidine-degrading enzyme controls stability of ethylene-producing cyanobacteria<\/a>,\u201d the researchers report their discovery and demonstration that a certain gene can induce stability in bacteria that produce ethylene. Their discovery is a welcome breakthrough, as past attempts at employing this ethylene pathway had led to genetic instability in the bacteria.<\/p>\n\n\n\n

\u201cUntil now, a major roadblock to photosynthetic ethylene production has come from the organism itself\u2014it creates a toxic byproduct alongside the ethylene,\u201d said Jianping Yu<\/strong>, an NREL author on the paper. \u201cWith this work, we now know that the toxic byproduct can be dealt with using a genetic technique.\u201d<\/p><\/blockquote>\n\n\n\n

Guanidine: An Unwanted Guest in Solar-Driven Ethylene Production<\/h3>\n\n\n\n

The researchers\u2019 intended approach is straightforward: Hijack the gene to produce ethylene  from a common plant pathogen (Pseudomonas Syringae<\/em>, a bacterium that causes brown spots on leaves), and introduce that gene into a cyanobacteria, which use photosynthesis for energy. If everything works correctly, the cyanobacteria will then convert solar radiation and CO2<\/sub> into ethylene; indeed, more efficiently than any other biological pathway. But instead, the cyanobacteria slowly died; the researchers showed that the introduced gene pathway also produces guanidine, a toxin that creates genetic instabilities in cyanobacteria.<\/p>\n\n\n\n

\u201cOur objective is to understand the source of guanidine toxicity in this pathway and how cells can thwart it. To that end, we now have a pretty compelling approach,\u201d Yu <\/strong>said.<\/p><\/blockquote>\n\n\n\n

Guanidine causes a disorder of pigment metabolism in cyanobacterial cells\u2014an obviously bad byproduct when the cells\u2019 purpose is to use its pigment to harvest light. Fortunately, a particular cyanobacteria beloved by scientists\u2014Synechocystis 6803\u2014<\/em>can degrade guanidine. The trick, then, is to capture that genetic mechanism and reinsert it into other cyanobacteria cells. In other words, introduce another<\/em> gene that stabilizes the first, and leads to unobstructed ethylene production.<\/p>\n\n\n\n

Genomic Stability for Enduring Ethylene Yields<\/h3>\n\n\n\n

The researchers hypothesized that a specific gene in Synechocystis 6803<\/em> was at play in the guanidine degradation, based on the gene\u2019s higher expression in the ethylene-producing strain and its sequence similarity to other known guanidine-related metabolic machinery. That guess was affirmed when the researchers knocked the gene out from the cyanobacterium and observed the cells\u2019 decline when exposed to guanidine. To further validate the gene\u2019s role in guanidine degradation, the researchers then added the gene to another species.<\/p>\n\n\n\n

In the other cyanobacterium\u2014Synechococcus 7942<\/em>, another favorite species that scientists engineered\u2014the research team assessed whether the gene conferred the same ability to degrade guanidine. Sure enough, just as in the first species, the modified cyanobacterium could metabolize the guanidine, thereby preventing genetic problems and enabling persistent ethylene production. For both organisms, the gene effectively neutralized guanidine, converting the toxic chemical into harmless urea and ammonia.<\/p>\n\n\n\n

\"The
The lower panel shows the Synechococcus 7942<\/em> ethylene-producing cyanobacteria strain, with unstable genome indicated by varied colony sizes. The smaller colonies contain the correct gene for ethylene-forming enzyme (EFE), and the large colonies contain mutated versions of the gene, resulting from guanidine toxicity, and do not produce ethylene. The upper panel shows the same strain with an introduced guanidinase gene for guanidine degradation (GD). These have more uniform colony size, the genome is stable, and ethylene productivity is stable as well. \u00a9<\/strong> NREL<\/figcaption><\/figure><\/div>\n\n\n\n

Opportunity for a Clean Chemical Alternative<\/h3>\n\n\n\n

Biologically produced ethylene is a double-win for clean energy\u2014it recycles CO2<\/sub> and displaces fossil-based feedstocks that industry currently depends on. Compared to other biological pathways, which use plant biomass as a starting material, the method pursued in this work is fueled directly by the sun, making it potentially more energetically favorable.<\/p>\n\n\n\n

Industrial application to decarbonize the chemical industry is tantalizing; hope persists for producing PVC pipes for clean water, and even in Mars colonization<\/a>. This work shows a possibility to scale up bioethylene production by clearing certain biological barriers. Future research could create even more efficient guanidine-degrading enzymes, possibly through evolution of the same gene described in this study. For now, the team\u2019s work advances the knowledge of guanidine metabolism in nature and demonstrates a functional approach for enhancing ethylene production.<\/p>\n\n\n\n

Their work was funded in part by the U.S. Department of Energy Bioenergy Technologies Office and follows on a foundational technology that earned an R&D 100 Award in 2015.<\/p>\n","protected":false},"excerpt":{"rendered":"

For decades engineers have dreamed of programming organisms to sustainably produce ethylene, a chemical that is nicknamed \u201cthe king of petrochemicals\u201d for its importance in plastics. Now, one hopeful pathway to this petrochemical is nearing reality, via a photosynthetic bacterium that is genetically specialized to turn sunlight and carbon dioxide (CO2) into ethylene. But before […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","nova_meta_subtitle":"A Genetic Sequence Allows Photosynthetic Organisms To Stably Produce Ethylene","footnotes":""},"categories":[5572],"tags":[5838,17280,15123,10408,13634],"supplier":[371,20444],"class_list":["post-110233","post","type-post","status-publish","format-standard","hentry","category-bio-based","tag-bioeconomy","tag-bioethylene","tag-cleanenergy","tag-greenchemistry","tag-photosynthesis","supplier-national-renewable-energy-laboratory-nrel","supplier-nature-journal"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/110233","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=110233"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/110233\/revisions"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=110233"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=110233"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=110233"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=110233"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}