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

20世纪世纪，材料制造取得了前所未有的进步，化学和机械工程方法使塑料、复合材料、气凝胶等成为可能。在21世纪的世纪，我们在生物工程方面的新发现为一种新的范例--生长工程材料（GEM）打开了大门。而不是混合在一起并对现有的散装材料进行化学改性，GEM将以精确，可持续的方式在体内生产，材料是由自然界制成的-细胞在微观尺度上共同工作，平行生长不同的聚合物，相互作用，形成自我图案化的复合材料。使用合成生物学方法，这个突破性的项目将开发和展示第一代GEM，通过共同培养一组我们已经证明可以作为一个稳定的财团一起生长的工程微生物来生产这些GEM。这些产生材料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GEM。这些都是重复的生物聚合物，其本身具有工业上有吸引力的特性;细菌制造的纳米纤维素非常纯，生物相容性好，具有高机械负荷能力，而酵母制造的ELP是环境响应性的，可以设计为由于盐，pH值或温度水平的变化而塌陷或延伸。通过培养工程细胞共同合成这两种生物材料，为制造令人兴奋的新材料提供了一条新途径，这些材料的性能超出了其组成部分。这种方法的灵感来自于自然，我们见证了植物通过掺入不同的聚合物（如木质素），将纤维素编织成机械坚固的复合材料，从而构建令人印象深刻的生物材料。例如，纤维素与其他生物聚合物在复合材料中的自然共生增强了植物细胞壁的抗压强度，也使新的特性得以出现。为了展示GEM的范例，我们的英国和美国团队将在这个项目中合作，合成和测试不同的ELP设计，以了解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。除此之外，我们将研究，工程和优化酵母菌株，使这些ELP蛋白可以有效地分泌到与纤维素生产细菌稳定共培养的工程酵母细胞的生长材料。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和低成本的生长培养基中生长出高产量的ELP-纤维素复合材料。我们将评估这些原型GEM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复合材料在微观尺度上的制造方式、地点和时间。这个雄心勃勃的跨学科研究项目将利用我们两个团队拥有国际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学遗传控制，一直到系统生物学、转录组学、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，以便DNA在微生物细胞中的写入方式的变化可以预测地导致材料及其特性的变化。我们的目标是实现GEM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，以便在未来利用这种方法。

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.