合成生物学在生物基塑料制造中的应用

合成生物学是以工程学思想为指导,对天然生物基因组进行改造和重构,合成新的生物元件,构建新的代谢途径,生产新产品或获得新表型的新兴学科。生物基塑料是以天然物质为原料在微生物作用或化学反应下生成的塑料。利用合成生物学改造工程菌株的方法制备合成生物基塑料已经成为学术界和产业界关注的热点。本文综述了合成生物学的发展和重要的合成生物学技术,重点综述了利用合成生物学技术构建聚羟基烷酸酯、尼龙、聚乳酸和丁二酸丁二醇酯等生物基塑料聚合物单体及其衍生物的代谢途径和工程优化领域的研究进展。     

合成生物学研究进展

合成生物学是以工程化设计思路,构建标准化的元器件和模块,改造已存在的天然系统或者从头合成全新的人工生命体系,实现在化学品合成(包括材料、能源和天然化合物)、医学、农业、环境等领域的应用。人们利用基本的生物学元件设计和构建了基因开关、振荡器、放大器、逻辑门、计数器等合成器件,实现对生命系统的重新编程并执行特殊功能。模块化处理生物的代谢途径,并在底盘细胞上进行组装和优化,可以实现大宗化学品和精细化学品的合成。目前人们已经在丁醇、异丁醇、青蒿素和紫杉醇等化合物的生物合成上取得了重要进展。近年来还发展了多种基因组编辑和组装技术,可精确地对基因组进行编辑,人们还成功地合成了噬菌体基因组、支原体基因组和酵母基因组。在未来的50～100年内,合成生物学将对人类的医疗、化学品制造(含药品)、军事产生渐进性的、渗透性的但颠覆性的意义。     

合成生物学在医药及能源领域的应用

合成生物学是以工程学思想为指导,对天然生物系统进行重新设计与改造,同时设计并合成新的生物元件、模块和系统的崭新学科。合成生物学是自然科学发展到现阶段的产物,并已经在医药、能源等领域取得了一些显著成果。本文综述了在工程细胞中利用合成生物学方法构建抗疟疾药物青蒿素的前体物青蒿二烯,抗癌药物紫杉醇的前体物紫杉二烯,以及脂肪酸酯、脂肪醇、高级醇的合成途径等研究进展。此外,一些重要的合成生物学相关技术,大大加速工程细胞的重构与进化,为构建应用于生产领域的新功能细胞提供方便实用的工具。     

微生物合成2,3-丁二醇的代谢工程

2,3-丁二醇（2,3-BD）是一种重要的微生物代谢产物,广泛应用于食品、医药、化工等多个领域。微生物合成2,3-BD的效率不高一直制约着其生物制造工业化进程,应用代谢工程的理论和方法优化微生物的代谢途径有望解决这一问题。本文全面总结了近年来微生物合成2,3-BD研究过程中的菌株改造和构建技术,包括过表达合成途径中的关键酶编码基因、敲除旁路代谢途径关键酶编码基因、应用辅因子工程手段对天然菌株代谢网络进行重新设计和合理改造,以及利用合成生物学技术在模式菌株中构建全新的代谢途径,实现2,3-BD的高效生物合成。最后,本文对未来的研究方向进行了展望,提出了进一步利用先进的合成生物学方法构建高效细胞工厂的指导性建议。     

Engineering Bacterial Cellulose by Synthetic Biology

Synthetic biology is an advanced form of genetic manipulation that applies the principles of modularity and engineering design to reprogram cells by changing their DNA. Over the last decade, synthetic biology has begun to be applied to bacteria that naturally produce biomaterials, in order to boost material production, change material properties and to add new functionalities to the resulting material. Recent work has used synthetic biology to engineer several Komagataeibacter strains; bacteria that naturally secrete large amounts of the versatile and promising material bacterial cellulose (BC). In this review, we summarize how genetic engineering, metabolic engineering and now synthetic biology have been used in Komagataeibacter strains to alter BC, improve its production and begin to add new functionalities into this easy-to-grow material. As well as describing the milestone advances, we also look forward to what will come next from engineering bacterial cellulose by synthetic biology.     

Recent advancements in bioreactions of cellular and cell-free systems: A study of bacterial cellulose as a model

Conventional approaches of regulating natural biochemical and biological processes are greatly hampered by the complexity of natural systems. Therefore, current biotechnological research is focused on improving biological systems and processes using advanced technologies such as genetic and metabolic engineering. These technologies, which employ principles of synthetic and systems biology, are greatly motivated by the diversity of living organisms to improve biological processes and allow the manipulation and reprogramming of target bioreactions and cellular systems. This review describes recent developments in cell biology, as well as genetic and metabolic engineering, and their role in enhancing biological processes. In particular, we illustrate recent advancements in genetic and metabolic engineering with respect to the production of bacterial cellulose (BC) using the model systems Gluconacetobacter xylinum and Gluconacetobacter hansenii. Besides, the cell-free enzyme system, representing the latest engineering strategies, has been comprehensively described. The content covered in the current review will lead readers to get an insight into developing novel metabolic pathways and engineering novel strains for enhanced production of BC and other bioproducts formation.     

微生物法生产1,3-丙二醇过程的代谢工程研究进展

代谢工程在微生物发酵法生产化工产品的过程中扮演着越来越重要的角色. 本研究以生物法生产1,3-丙二醇所涉及的关键酶、代谢途径及其改造为考察对象,系统综述了微生物法生产1,3-丙二醇所涉及的代谢工程技术、最新应用情况及其进展,并展望了未来的发展趋势.     

甲基营养型大肠杆菌构建策略的研究进展

利用微生物细胞工厂实现原料转化和产品合成是绿色生物制造的核心。然而,当前生物制造仍以富含糖类的谷物粮食为主要原料,存在“与民争粮”的争议,亟需开发非粮原料。甲醇作为煤化工产业中的重要产品,具有来源广、价格低、还原性强等优势,有替代粮食原料的潜力。天然甲基营养菌可利用甲醇生产单细胞蛋白和各种氨基酸,但存在理论收率低、遗传改造工具不足等缺点。随着合成生物学的发展,以大肠杆菌等模式生物作为底盘细胞构建人工甲基营养菌,实现甲醇到各种化学品的生产已成为研究热点。本文总结了多种甲基营养型大肠杆菌的构建策略,明确了影响天然路径代谢的关键因素与代谢过程中的重要中间产物,概括了各种天然路径在大肠杆菌中的优化策略与人工新路径的构建方法,并对工程菌株的优化提出了展望。     

生物制造过程中的微生物生长与调控

提高生物基产品的产量和生产效率是生物制造发展的目标。由于微生物具有生长快、营养要求简单和基因操作简便等特点,常用作生物基产品制造过程中的底盘宿主,因此,产品制造过程中微生物细胞的生长与调控尤为重要,其生长调控会直接或间接地影响生物基产品的合成效率。微生物的生长不仅受外界环境如温度、溶氧量、pH等的影响,而且还受微生物本身的生长与调控机制如细胞分裂调控、必需基因表达调控、程序化死亡等的影响。本文综述了利用分子生物学、合成生物学和系统生物学等方法对微生物细胞生长和分裂过程进行分子调控,以提高生物反应速率和目标产物的产量,为化工、食品、生物医药以及环境保护等领域构建高效的生物制造工艺提供新思路。     

Efficient Large-Scale and Scarless Genome Engineering Enables the Construction and Screening of Bacillus subtilis Biofuel Overproducers

Bacillus subtilis is a versatile microbial cell factory that can produce valuable proteins and value-added chemicals. Long fragment editing techniques are of great importance for accelerating bacterial genome engineering to obtain desirable and genetically stable host strains. Herein, we develop an efficient CRISPR-Cas9 method for large-scale and scarless genome engineering in the Bacillus subtilis genome, which can delete up to 134.3 kb DNA fragments, 3.5 times as long as the previous report, with a positivity rate of 100%. The effects of using a heterologous NHEJ system, linear donor DNA, and various donor DNA length on the engineering efficiencies were also investigated. The CRISPR-Cas9 method was then utilized for Bacillus subtilis genome simplification and construction of a series of individual and cumulative deletion mutants, which are further screened for overproducer of isobutanol, a new generation biofuel. These results suggest that the method is a powerful genome engineering tool for constructing and screening engineered host strains with enhanced capabilities, highlighting the potential for synthetic biology and metabolic engineering.     

Efficient production of chemicals from microorganism by metabolic engineering and synthetic biology

The use of traditional chemical catalysis to produce chemicals has a series of drawbacks, such as high dependence on fossil resources, high energy consumption, and environmental pollution. With the development of synthetic biology and metabolic engineering, the use of renewable biomass raw materials for chemicals synthesis by constructing efficient microbial cell factories is a green way to replace traditional chemical catalysis and traditional microbial fermentation. This review mainly summarizes several types of bulk chemicals and high value-added chemicals using metabolic engineering and synthetic biology strategies to achieve efficient microbial production. In addition, this review also summarizes several strategies for effectively regulating microbial cell metabolism. These strategies can achieve the coupling balance of material and energy by regulating intracellular material metabolism or energy metabolism, and promote the efficient production of target chemicals by microorganisms.     

代谢工程改造解脂耶氏酵母生产脂肪酸及其衍生物

微生物来源的脂肪酸及其衍生物广泛应用于能源、材料和营养化学品等领域,可用于生产航空燃油、聚合物、增塑剂、润滑剂和食品添加剂等。解脂耶氏酵母是一种研究最为透彻的产油脂酵母,具有高产各种脂肪酸及其衍生物的潜力。本文综述了近年来解脂耶氏酵母遗传操作工具的发展,并介绍了通过代谢工程技术改造解脂耶氏酵母生产脂肪酸及其衍生物的进展,在此基础上,展望了通过构建解脂耶氏酵母细胞工厂合成特定脂肪酸及其衍生物的未来发展方向。     

Cell-free synthetic biology in the new era of enzyme engineering

With the gradual rise of enzyme engineering, it has played an essential role in synthetic biology, medicine, and biomanufacturing. However, due to the limitation of the cell membrane, the complexity of cellular metabolism, the difficulty of controlling the reaction environment, and the toxicity of some metabolic products in traditional in vivo enzyme engineering, it is usually problematic to express functional enzymes and produce a high yield of synthesized compounds. Recently, cell-free synthetic biology methods for enzyme engineering have been proposed as alternative strategies. This cell-free method has no limitation of the cell membrane and no need to maintain cell viability, and each biosynthetic pathway is highly flexible. This property makes cell-free approaches suitable for the production of valuable products such as functional enzymes and chemicals that are difficult to synthesize. This article aims to discuss the latest advances in cell-free enzyme engineering, assess the trend of this developing topical filed, and analyze its prospects.     

基于天然高分子的生物基可降解复合膜的研究进展

针对难降解废弃塑料对自然环境造成的影响,采用生物基原料制备全生物降解材料,从根源上解决塑料污染.介绍了蛋白复合膜、淀粉复合膜和多糖复合膜3种生物基降解薄膜的性能及应用方向,为推动全生物降解材料的发展提供参考.     

核糖核酸开关用于微生物细胞工厂的智能与精细调控

利用代谢工程与合成生物技术对细胞内复杂的代谢网络和调控网络进行重构和改造,以建立合成新化合物或提高目标产物产量的微生物细胞工厂是当今绿色化工技术发展的方向之一。微生物代谢途径的调控受环境和遗传的双重影响,细胞通过全局转录因子、信使分子和反馈抑制等方式响应环境变化来维持细胞的内稳态;同时细胞还受自身遗传基因线路的调控,在转录、翻译以及翻译后修饰过程中调控特定基因的表达。核糖核酸开关是一类调控基因线路表达的RNA元件,通过与金属离子、糖类衍生物、氨基酸、核酸衍生物以及辅酶等特异性配体结合发生的构象变化,从而启动或阻断mRNA的转录、翻译、拼接等过程来调控基因的表达。核糖核酸开关作为天然的生物感受器和效应器通过人工设计可成为微生物细胞工厂智能化和精细化调控的分子工具,并在化工、医药、环保、食品等领域得到广泛应用。     

他克莫司微生物合成的研究进展

介绍了他克莫司的理化特征和免疫抑制活性,重点阐述了他克莫司发酵法生产的研究现状,着重介绍了他克莫司的合成基因簇及代谢途径研究进展,对他克莫司代谢工程改造进行综述并对今后的研究趋势进行了展望--结合系统生物学为已有的他克莫司菌株进一步进行代谢工程改造提供指导;通过合成生物学构建他克莫司合成途径全新高效的前体关键酶。     

面向资源与环境的生物基化学品技术创新与展望

生物基化学品是以可再生的生物质为原料,以生物细胞或酶蛋白为催化剂合成的产品。由于摆脱了对化石原料的依赖,同时避免了石油基产品制备过程的高能耗高污染,为了资源和环境的绿色、可持续发展,以可再生的生物质资源为原料,以生物转化技术制备化学品是未来发展的主要趋势。本文对目前国内外生物基化学品研发及生产概况进行综述,预测生物基化学品制造业将朝着为原料多元化、生物转化过程高效化、产品高值化的方向发展,针对生物转化过程高效化的关键科学问题进行深入探讨,提出生物学科与其他学科交叉融合是生物基化学品制造技术未来的发展方向,包括生物技术自身融合、生物与化工技术融合及生物与过程控制技术融合。     

工程塑料在汽车车灯上的应用介绍

车灯是汽车上必不可少的一个零部件,从20世纪80年代起,工程塑料应用于汽车车灯领域,给车灯发展更带来新的空间。本文介绍了工程塑料在车灯上应用情况,阐述了几种常用的材料在灯具上使用案例,辅助于加工过程和图片说明,工程塑料在车灯中应用体现了较好地优越性,广泛性和普及性。     

Multi-Site Incorporation of Nonstandard Amino Acids into Protein-Based Biomaterials

The ability of natural biomaterials to shape, support, and orchestrate function inspires our efforts to produce functional materials. Guided by protein-based biomaterials, template-directed incorporation of synthetic building blocks, such as nonstandard amino acids (nsAAs), can expand the functions of biomaterials by endowing them with new physical and biophysical properties. In this short review, we describe existing technologies for multi-site nsAA incorporation into proteins. We then discuss examples of the application of this technology for engineering new functions in artificial biopolymers, for creating bio-inspired adhesives, and for improving the stability of biomaterials. We conclude by briefly discussing recent advances in synthetic biology that have the potential to expand our ability to design protein-based biomaterials composed of numerous and increasingly exotic nonstandard monomers.