CBET-EPSRC - Grown Engineered Materials (GEMs): synthetic consortia for biomanufacturing tunable composites

20世纪见证了材料制造前所未有的进步，化学和机械工程方法使塑料、复合材料、气凝胶等成为可能。如今，在21世纪，我们在生物工程领域新发现的能力为一种新的范式-生长工程材料(GEM)打开了大门。宝石将以自然制造的精确、可持续的方式在体内生产，而不是混合在一起并对现有的块状材料进行异地化学修饰--细胞在微观尺度上协同工作，并行生长不同的聚合物，这些聚合物相互作用形成自图案化的复合材料。使用合成生物学的方法，这个突破性的项目将开发和展示第一代宝石，通过共同培养一组工程微生物来生产这些宝石，我们已经证明这些微生物可以作为一个稳定的联合体一起生长。这些产生物质的微生物将产生由纳米纤维素纤维和弹性蛋白样多肽(ELP)制成的宝石。这两种聚合物本身都是具有工业吸引力的重复生物聚合物；细菌制造的纳米纤维素具有非常高的纯度、生物相容性和高机械负荷能力，而酵母制造的ELP是环境响应型的，可以设计成随着盐水平、pH或温度的变化而崩溃或伸展。让这两种生物材料从正在生长的工程细胞中共同合成在一起，为制造具有超出其组成部分的性能的令人兴奋的新材料提供了一条新的途径。这种方法的灵感来自大自然，在那里，我们看到植物通过加入不同的聚合物，如木质素，从编织纤维素到机械坚固的复合材料，建造出令人印象深刻的生物材料。例如，在与其他生物聚合物的复合材料中，纤维素的自然联合生产提高了植物细胞壁的抗压强度，并使新的特征得以出现。为了展示GEMS的范例，我们的英国和美国团队将在这个项目中合作，合成并测试不同的ELP设计，以确定蛋白质如何在不断增长的纳米纤维素纤维网络中相互作用。此外，我们将研究、设计和优化酵母菌株，以便这些ELP蛋白可以通过工程酵母细胞与产生纤维素的细菌稳定地共培养而有效地分泌到生长材料中。到项目结束时，我们希望能够在短短几天内从我们的酵母和细菌的混合物以及低成本的生长介质中培育出高产量的ELP-纤维素复合材料。我们将评估这些原型宝石的材料特性，然后使用合成生物学工具，如光遗传学和图案形成，来控制如何、在哪里和何时在微观尺度上制造复合材料。这个雄心勃勃的跨学科研究项目将利用我们两个团队在国际上拥有专业知识的许多最先进的生物工程方法。从合成蛋白质聚合物设计、菌株优化和合成生物遗传控制，一直到系统生物学、转录学、机器学习和生物材料表征。我们计划生产一系列遗传可调的ELP-纤维素复合材料，这样DNA在微生物细胞中写入方式的变化就可以预测地导致材料及其性能的变化。我们的目标是实现宝石的范例，并为其他人提供蓝图、工程菌株和合成生物学工具包，以便在未来使用这种方法。

The 20th century saw unprecedented advances in the manufacture of materials, with chemical and mechanical engineering approaches enabling plastics, composites, aerogels and more. Now in the 21st century, our newfound abilities in biological engineering open the door to a new paradigm - Grown Engineered Materials (GEMs). Rather than blending together and chemically-modifying existing bulk materials ex situ, GEMs will be produced in vivo in the precise, sustainable way that materials are made by nature - with cells working together at the micro scale to grow different polymers in parallel that interact to form self-patterned composites. Using a synthetic biology approach, this breakthrough project will develop and demonstrate the first generation of GEMs, producing these by co-cultivating a set of engineered microbes that we have demonstrated can be grown together as a stable consortium. These material-producing microbes will produce GEMs made from nanocellulose fibres and elastin-like polypeptides (ELPs). These are both repetitive biopolymers that on their own have industrially-attractive properties; bacterial-made nanocellulose is exceptionally pure, biocompatible and possess a high mechanical load capability, while yeast-made ELPs are environment-responsive and can be designed to collapse or extend due to changes in levels of salt, pH or temperature. Having these two biomaterials co-synthesised together from growing engineered cells offers a novel route to making exciting new materials that offer properties beyond those of their constituent parts. This approach is inspired by nature, where we witness plants building impressive biomaterials from weaving cellulose into a mechanically-robust composites by incorporation of different polymers such as lignin. For example, the natural co-production of cellulose in composites with other biopolymers enhances the compressive strength of plant cell walls and also enables new characteristics to emerge.To demonstrate the paradigm of GEMs, our UK and US groups will work together in this project to synthesise and test different ELP designs for how the proteins interact within a growing nanocellulose fibre network. Alongside this we will study, engineer and optimise yeast strains so that these ELP proteins can be efficiently secreted into the growing material by engineered yeast cells that stably co-culture with the cellulose-producing bacteria. By the end of the project we expect to be able to grow high yields of ELP-cellulose composites in just a few days from only our mix of yeasts and bacteria and low-cost growth media. We will assess the material properties of these prototype GEMs and then use synthetic biology tools, such as optogenetics and pattern formation to control how, where and when the composites are made at the micro-scale. This ambitious interdisciplinary research project will utilise many state-of-the-art approaches to biological engineering that our two groups have international expertise in. From synthetic protein polymer design, strain optimisation and synthetic biology genetic control, right through to systems biology, transcriptomics, machine learning and biomaterial characterisation. We plan to produce a range of ELP-cellulose composite materials that are genetically-tunable, so that changes in the way DNA is written in the microbial cells can predictably lead to changes in the materials and their properties. Our aim is to realise the paradigm of GEMs and provide the blueprint, engineered strains and synthetic biology toolkit for others to utilise this approach in the future.