Engineering synthetic pathways to bio-ethylene production in Cupriavidus necator

Cupriavidus necator 中生物乙烯生产的工程合成途径

• 批准号: 1803753
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1803753
• 关键词: Engineering; synthetic; pathways; bio; ethylene

Background: Ethylene is currently produced from stream cracking of ethane which produces large quantaties of CO2, contributing to global warming. In 2000, steam cracking had a primary energy use of 3 billion Gigajoules and accounted for approximately 200 millions tons of CO2 emissions. Ethylene is the monomer for the most common plastic, polyethylene, and annual global production is approximately 80 million tons. Finding a sustainable or carbon neutral alternative to ethylene production is imperative. Cupriavidus necator is a gram-negative soil bacterium, capable of growing on CO2 and H2 enabling low carbon fuels and chemicals to be produced with minimal release of CO2 to the environment. Research in this area is at the forefront of the green revolution and the production of bio-ethylene from sustainable or carbon neutral sources further spearheads a diminished reliance on fossils fuels throughout the world.Aim: The aim of this project is to engineer Cupriavidus necator as a platform for the production of hydrocarbon-based products such as ethylene. As proof of concept, we have expressed the efe genes (ethylene forming enzyme) from P. syringae pv. paseolicola, which is sufficient for ethylene production in heterologous hosts and Ralstonia solanacearum. We have generated ethylene from minimal media and from CO2; and we are now in the process of improving production through directed evolution and metabolic engineering. As part of this process we would like to engineer a synthetic pathway for ethylene production utlising the Yang pathway from plants. This provides an exciting opportunity to implement a novel pathway in C. necator and link ethylene production to growth. Ethylene is efficiently biosynthesized from 1-aminocyclopropane-1-carboxylic acid (ACC) (Zhou et al., 2002), which is itself derived from methionine as a branch of the Yang cycle (Wang et al., 2002). This process is energetically efficient as it preserves the high-energy methionine thioether bond. This pathway utilises SAM synthtase, ACC synthase and ACC oxidase. The conversion of 1-amino-cyclopropane-1-carboxylic acid (ACC) to ethylene releases cyanoformic acid, which spontaneously decarboxylates to release cyanide, which is principally detoxified by the CAS pathway (machingura et al., 2016). The implementation of this pathway will provide a mechanism for detoxifiying cyanide in C. necator. Training: The project will allow for training in a unique multidisciplinary environment, incorporating genomic engineering, gas fermentation, synthetic biology, cutting edge molecular biology and systems biology modelling. The project will provide the student with a vast array of transferable skills, highly prized by employers in the growing bioeconomy. The project will also provide several high impact publications. This translational project will be carried out within the BBSRC/EPSRC Synthetic Biology Research Centre (SBRC) at Nottingham which comprises 70+ graduate and postdoctoral researchers (www.clostron.com/people.php) and a current budget of £27M.

背景：乙烯目前是由Samene的流破裂产生的，Samene产生了大量CO2，从而有助于全球变暖。在2000年，蒸汽破裂的主要能源使用了30亿千兆joules，占二氧化碳排放量约2亿吨。乙烯是最常见的塑料，聚乙烯和年度全球生产的月份约为8000万吨。必须找到可持续的或碳中性替代乙烯生产的方法。丘比德斯固定物是一种革兰氏阴性的土壤细菌，能够在CO2和H2上生长，从而使低碳燃料和化学物质能够最小的二氧化碳释放到环境中产生。该领域的研究处于绿色革命的最前沿，以及从可持续或碳中性来源生产的生物乙烯，进一步率降低了对全球化石燃料的依赖。作为概念证明，我们从丁香假单胞菌PV表达了EFE基因（乙烯形成酶）。 paseolicola，足以在异源宿主和摩尔斯托尼亚溶胶植物中产生乙烯。我们从最小培养基和CO2产生了乙烯；现在，我们正在通过定向进化和代谢工程来改善生产。作为此过程的一部分，我们想设计一种合成途径，以使乙烯生产从植物中延伸YANG途径。这为在C. necator中实施新的途径提供了一个令人兴奋的机会，并将乙烯生产与增长联系起来。乙烯是从1-氨基丙烷-1-羧酸（ACC）（Zhou等，2002）中有效生物合成的，该乙烯本身是从甲基氨酸中得出的（Wang等，2002）。该过程实质上是有效的，因为它保留了高能蛋氨酸硫醇键。该途径利用SAM合酶，ACC合酶和ACC氧化物。 1-氨基 - 环丙烷-1-羧酸（ACC）转化为乙烯释放蓝酸，蓝酸释放蓝酸，它发起了类似脱羧的脱羧酸酯释放氰化物，该氰化物主要由Cas的实施来释放该途径（Machiningura等，2016）。该途径的实施将为C. necator中的排毒氰化物提供机制。培训：该项目将允许在独特的多学科环境中进行培训，并结合基因组工程，气体发酵，合成生物学，尖端分子生物学和系统生物学建模。该项目将为学生提供各种可转移技能，这些技能在不断增长的生物经济学中受到员工的高度评价。该项目还将提供几个高影响力出版物。该翻译项目将在诺丁汉的BBSRC/EPSRC合成生物学研究中心（SBRC）内进行，该研究中心包括70多名毕业生和博士后研究人员（www.clostron.com/people.php）和当前的2700万英镑预算。