代谢工程——生物工程学科的新兴研究领域

代谢工程包括推理性代谢工程及逆代谢工程。针对限制生物活性的因素 ,从不同的途径设计代谢改变策略 ,采用重组DNA技术解除或削弱该影响 ,提高目的产物的产率 ,是生化工程学科提高生物活性的新兴研究领域。讨论了推理性代谢工程及逆代谢工程的设计及应用。     

代谢工程的发展及其应用

本首先论述了代谢工程的代谢网络理论、代谢分析、节点分析和中心代谢物作用机理等代谢工程理论基础。然后,分析了代谢工程的各种具体设计思路,并以实际例子作了详细说明。另外还对代谢工程的新兴研究方向－逆代谢工程进行了简单说明。     

系统代谢工程在微生物定向进化中的应用

系统生物学的迅速发展使人们能够从整体水平上理解细胞的生理生化特性并调控其代谢.系统代谢工程的主要应用之一是以系统生物学为基础对微生物进行定向进化,以期增强细胞对环境胁迫的耐受性,提高目标产品的产量.前者多采用全局转录机制工程和逆代谢工程的方法;后者主要通过设计并导入最优化路径,重构代谢网络及基因的模拟敲除和湿法验证等策略实现.本文综述了利用系统代谢工程解决细胞生物工程几个主要问题的技术及其应用进展.     

酿酒酵母代谢工程技术

自20世纪90年代初期诞生以来,代谢工程历经了30年的快速发展。作为代谢工程的首选底盘细胞之一,酿酒酵母细胞工厂已被广泛应用于大量大宗化学品和新型高附加值生物活性物质的生物制造,在能源、医药和环境等领域取得了巨大的突破。近年来,合成生物学、生物信息学以及机器学习等相关技术也极大地促进了代谢工程的技术发展和应用。文中回顾了近30年来酿酒酵母代谢工程重要的技术发展,首先总结了经典代谢工程的常用方法和策略,以及在此基础上发展而来的系统代谢工程和合成生物学驱动的代谢工程技术。最后结合最新技术发展趋势,展望了未来酿酒酵母代谢工程发展的新方向。     

代谢工程：一项不断发展的菌株改造技术

对代谢工程的发展进行了简要回顾,分析了代谢工程发展的推动力,重点评述了本期专栏发表的12篇代谢工程和细胞工厂方面的论文。     

《生物工程学报》2010年“代谢工程”专刊征稿通知

<正>代谢工程自1991年诞生以来,在改造植物、动物、微生物的代谢功能方面得到了广泛的应用。为了展现代谢工程科研工作者取得的最新进展,促进我国代谢工程研究的进步和发展,本刊2009年第9期设立了"代谢工程与细胞工厂"专栏,国内该领域著名学者对代谢工程的技术发展进行了总结,介绍了合成生物学等新理论和新技术,并发表了     

《生物工程学报》2010年“代谢工程”专刊征稿通知

<正>代谢工程自1991年诞生以来,在改造植物、动物、微生物的代谢功能方面得到了广泛的应用。为了展现代谢工程科研工作者取得的最新进展,促进我国代谢工程研究的进步和发展,本刊2009年第9期设立了"代谢工程与细胞工厂"专栏,国内     

历久弥新：进化中的代谢工程

20世纪90年代,Bailey及Stephanopoulos等提出了经典代谢工程的理念,旨在利用DNA重组技术对代谢网络进行改造,以达到细胞性能改善,目标产物增加的目的。自代谢工程诞生以来的30年,生命科学蓬勃发展,基因组学、系统生物学、合成生物学等新学科不断涌现,为代谢工程的发展注入了新的内涵与活力。经典代谢工程研究已进入到前所未有的系统代谢工程阶段。组学技术、基因组代谢模型、元件组装、回路设计、动态控制、基因组编辑等合成生物学工具与策略的应用,大大提升了复杂代谢的设计与合成能力;机器学习的介入以及进化工程与代谢工程的结合,为系统代谢工程的未来开辟了新的方向。文中对过去30年代谢工程的发展趋势作了梳理,介绍了代谢工程在发展中不断创新的理论与方法及其应用。     

代谢工程发展20年

代谢工程从上世纪90年代初期发展至今已有20年历史,对微生物发酵工业的发展起到了极大的推动作用。以下回顾了代谢工程发展至今的三个重要阶段,讨论了各阶段中代谢工程在技术方面的进展及其对微生物发酵工业的促进作用。最后还讨论了代谢工程将来发展中的关键问题及解决策略。     

氨基酸生产的代谢工程研究进展与发展趋势

氨基酸发酵是我国发酵工业的支柱产业,近年来,随着代谢工程的快速发展,氨基酸的代谢工程育种蓬勃发展。传统的正向代谢工程、基于组学分析与计算机模拟的反向代谢工程以及借鉴自然进化的进化代谢工程,都有越来越多的应用。在氨基酸的工业生产中涌现出了一系列具有高效生产、抗逆性强等优良性状的菌株。日益剧烈的市场竞争对菌株的选育提出了新的要求,如开发高附加值氨基酸品种、菌株代谢的动态调控、适应新工艺的要求等。文中介绍了氨基酸生产相关的代谢工程研究进展以及未来的发展趋势。     

Distinguishing ecological engineering from environmental engineering

This paper uses complex system thinking to identify key peculiarities of ecological engineering. In particular it focuses on the distinction between the purpose-driven design of structures in environmental engineering and the natural process of self-organization characteristic of life, which needs to be integrated into ecological engineering.Conventional engineering addresses the problem of fabrication of an organized structure, say a road, which reflects a goal at the outset, as well as considerations external to the road. At the outset there is an essence of which the organized structure is a realization. This realization belongs to a certain type (apartment building, suspension bridge). The type is in relation to: (a) the expected contexts (e.g. housing in Manhattan, a bridge in rural Africa) and (b) location-specific socio-economic constraints (low/high economic budget). Conventional engineering does not question the goals of the selected plan and can only object to the feasibility of a proposed typology in a given context. Engineers deal with the challenge of the realization of a plan at a given point in space and time.The central dogma of biology identifies organisms as informationally-closed and this makes possible their use as machines. Ecological systems, on the contrary, are informationally-open. They cannot be used as machines to create functional structures, because they are becoming in time. For engineered structures to work it is usually required that there is (1) stability of system components; (2) admissibility of a workable context; (3) validity of purpose and concept. Ecologically-engineered structures challenge these requirements because of specificity of required environments and lability of system parts over the time the engineered structure functions. Other engineering is better if it achieves flexibility, but ecological engineering must be so flexible as to take on a looping character that updates the system to meet changing requirements. Accordingly, the original goals cannot be taken for granted later in the process of ecological engineering. Ecological engineering has to be a flexible iterative process of design, in which the designer must continually update goals, essences, typologies and processes of realization.     

Antibody engineering

Monoclonal antibodies (Mabs) have been used as diagnostic and analytical reagents since hybridoma technology was invented in 1975. In recent years, antibodies have become increasingly accepted as therapeutics for human diseases, particularly for cancer, viral infection and autoimmune disorders. An indication of the emerging significance of antibody-based therapeutics is that over a third of the proteins currently undergoing clinical trials in the United States are antibodies. Until the late 1980's, antibody technology relied primarily on animal immunization and the expression of engineered antibodies. However, the development of methods for the expression of antibody fragments in bacteria and powerful techniques for screening combinatorial libraries, together with the accumulating structure-function data base of antibodies, have opened unlimited opportunities for the engineering of antibodies with tailor-made properties for specific applications. Antibodies of low immunogenicity, suitable for human therapy andin vivo diagnosis, can now be developed with relative ease. Here, antibody structure-function and antibody engineering technologies are described.     

Protein engineering

The techniques of protein engineering are proving to be a revolutionary experimental tool for understanding protein structure-function relationships. Even at this early stage, proteins of improved characteristics for specific industrial and therapeutic uses have already been produced. Tailoring enzymatic properties for non-physiological substrate conditions, altering pH optima, changing substrate specificity, and improving stability have already been demonstrated to be feasible. Nevertheless, the ability to make useful proteins which radically differ from a natural structure or designing altogether new structures exceeds present understanding.     

Anti-apoptosis engineering

An increased understanding of apoptosis makes anti-apoptosis engineering possible, which is an approach used to inhibit apoptosis for the purpose of therapeutic, or industrial applications in the treatment of the diseases associated with increased apoptosis, or to improve the productivity of animal cell cultures, respectively. Some known anti-apoptotic proteins are the Bcl-2 family, IAP (inhibitor of apoptosis) and Hsps (heat shock proteins), with which anti-apoptosis engineering has progressed. This article reviews anti-apoptosis engineering using known anti-apoptotic compounds, and introduces a 30 K protein, isolated from silkworm hemolymph, as a novel anti-apoptotic protein, that shows no homology with other known anti-apoptotic proteins. The regulation of apoptosis, using anti-apoptotic proteins and genes originating from the silkworm,Bombyx mori, may provide a new strategy in this field.     

Metabolic engineering

Metabolic engineering has developed as a very powerful approach to optimising industrial fermentation processes through the introduction of directed genetic changes using recombinant DNA technology. Successful metabolic engineering starts with a careful analysis of cellular function; based on the results of this analysis, an improved strain is designed and subsequently constructed by genetic engineering. In recent years some very powerful tools have been developed, both for analysing cellular function and for introducing directed genetic changes. In this paper, some of these tools are reviewed and many examples of metabolic engineering are presented to illustrate the power of the technology. The examples are categorised according to the approach taken or the aim: (1) heterologous protein production, (2) extension of substrate range, (3) pathways leading to new products, (4) pathways for degradation of xenobiotics, (5) improvement of overall cellular physiology, (6) elimination or reduction of by-product formation, and (7) improvement of yield or productivity.     

Antibody engineering

The antibody molecule is a therapeutic agent, designed by nature to bind to a wide range of antigen molecules and to trigger effector functions, such as complement lysis and cell-mediated killing. The genes encoding antibodies can be manipulated in vitro, allowing the binding sites for antigen and effector molecules to be dissected, and new properties to be engineered. The future for the application of engineered antibodies in medicine is reviewed in the context of the past century.     

Chromosomal engineering

Artificial chromosomes (ACs) are engineered chromosomes with defined genetic contents that can function as non-integrating vectors with large carrying capacity and stability. The large carrying capacity allows the engineering of ACs with multiple copies of the same transgene, gene complexes, and to include regulatory elements necessary for the regulated expression of transgene(s). Artificial chromosome based systems are composed of AC engineered to harbor and express gene(s) of interest and an appropriate recombination system for 'custom' engineering of ACs. These systems have the potential to become an efficient tool in diverse gene technology applications such as cellular protein manufacturing, transgenic animal production, and ultimately gene therapy. Recent advances in artificial chromosome technologies outline the value of these systems and justify the future research efforts to overcome the obstacles in exploring their full capabilities.     

Lignin engineering

Lignins are aromatic polymers that are present mainly in secondarily thickened plant cell walls. Several decades of research have elucidated the main biosynthetic routes toward the monolignols and demonstrated that lignin amounts can be engineered and that plants can cope with large shifts in p-hydroxyphenyl/guaiacyl/syringyl (H/G/S) lignin compositional ratios. It has also become clear that lignins incorporate many more units than the three monolignols described in biochemistry textbooks. Together with the theory that lignin polymerization is under chemical control, observations hint at opportunities to design lignin structure to the needs of agriculture. An increasing number of examples illustrates that lignin engineering can improve the processing efficiency of plant biomass for pulping, forage digestibility and biofuels. Systems approaches, in which the plant's response to engineering of a single gene in the pathway is studied at the organismal level, are beginning to shed light on the interaction of lignin biosynthesis with other metabolic pathways and processes.