乳酸菌生理功能的系统解析与代谢调控

作为工业化的细胞工厂,乳酸菌广泛应用于食品、农业和医药等行业。然而在乳酸菌的工业生产中以及作为益生菌在人体胃肠道系统中都会面临多种环境胁迫,这些胁迫环境严重影响乳酸菌的生理功能,从而影响食品微生物制造的效率。近年来,随着代谢工程和系统生物学的发展,为乳酸菌生理功能的改造带来了前所未有的机遇。本文综述了系统生物学和代谢工程在乳酸菌生理功能的优化和调控中的具体应用。     

调控乳酸菌酸胁迫抗性研究进展

作为工业化的细胞工厂,乳酸菌广泛应用于食品、农业和医药等行业。酸胁迫是乳酸菌在发酵生产以及作为益生菌在人体胃肠道系统中广泛存在的一种环境胁迫,严重影响乳酸菌的生理功能。近年来,随着系统生物学和代谢工程等技术的发展,为进一步揭示乳酸菌酸胁迫抗性机制并提高其耐酸性能带来了可能。本文综述了乳酸菌酸胁迫研究进展,介绍了乳酸菌应对酸胁迫的生理机制,并提出了提升乳酸菌酸胁迫抗性的策略。     

代谢工程应用研究进展

代谢工程发展已有二十多年的时间,其利用重组DNA技术,调控细胞生理功能,在微生物、植物和动物细胞中得到了广泛的应用。综述了代谢工程在微生物、植物和动物细胞中应用研究的最新进展,并对其今后发展方向做出展望。     

代谢工程中基因修饰与基因表达的工具

代谢工程利用重组DNA技术导入定向改造的基因 ,以改进微生物细胞的某些代谢特性 ,已经发展成为一个工业微生物育种和优化发酵过程的强有力工具。基因的修饰与表达是代谢工程的重要组成部分。本文介绍了近年来代谢工程中基因修饰与表达所用的工具方面的进展。     

耐受性工程调控微生物细胞工厂胁迫抗性

微生物细胞工厂的生产效率是由菌株生长性能、产品合成能力和胁迫抗性共同决定的,其中增强微生物细胞工厂的胁迫抗性是关键.耐受性工程基于微生物细胞工厂抵御胁迫压力的应激反应机制,通过巩固壁膜屏障增强胁迫防御能力,加快应激反应提高损伤修复能力,创制耐受进化工具筛选鲁棒性增强的工业微生物.文中分析归纳了耐受性工程的调控策略,并展...     

谷氨酸棒杆菌的代谢工程使能技术研究进展

谷氨酸棒杆菌Corynebacterium glutamicum是重要的工业微生物,尤其是在氨基酸工业中,每年用于600余万t氨基酸的生物制造。近年来,谷氨酸棒杆菌代谢工程使能技术正在不断完善,不仅加快了细胞工厂的创建和优化,拓展了底物谱和产物谱,也推动了谷氨酸棒杆菌的基础研究,使谷氨酸棒杆菌成为代谢工程的理想底盘细胞。文中综述了近期针对谷氨酸棒杆菌开发的代谢工程使能技术,着重介绍了基于CRISPR的基因组编辑、基因表达调控、适应性进化和生物传感器等技术的开发和应用。     

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.     

丝状真菌代谢工程研究进展

丝状真菌(Filamentous fungi)作为重要的工业发酵微生物,在有机酸、蛋白质及次级代谢产物等关键生物基产品生产方面发挥着重要作用.自20世纪90年代代谢工程理念提出以来,尤其是代谢工程使能技术的创新及发展,极大地促进了丝状真菌细胞工厂的构建及其在工业发酵领域的应用.文中将系统介绍近年来丝状真菌代谢工程技术的...     

微生物代谢工程原理与应用

代谢工程是利用分子生物学原理系统分析细胞代谢网络,并通过DNA重组技术和应用分析生物学相关的遗传学手段对细胞进行有精确目标的基因操作,改变微生物原有的代谢或调节系统,实现目的产物代谢活性的提高。代谢工程综合了生物化学、化学工程、数学分析等多学科内容,是当前国内外学者研究热点之一。论述了微生物代谢工程的理论基础及其应用进展和前景。     

启动子和细胞全局转录机制的定向进化在微生物代谢工程中的应用

通过随机突变和定向选择而进行的定向进化(又称分子进化或人工进化)在改造酶的催化特性和稳定性、扩展酶的底物范围等方面具有广泛的应用。近年来,定向进化也开始应用在对结构基因的启动子区域和具有调节功能的蛋白如转录因子等进行代谢工程改造,并成功选育了对环境胁迫因素具有较强耐受性,以及发酵效率提高的微生物菌种。以下着重介绍近年来启动子的定向进化,包括启动子的强度和调节功能的分子进化,以及细胞全局转录工程等技术在微生物代谢工程中的应用,这些定向进化技术使人们可以更精细地调节基因表达水平,并可同时改变细胞内多个基因的转录水平,是代谢工程研究新的有力工具。     

微生物发酵法生产L-色氨酸的代谢工程研究

L-色氨酸作为人体内的一种必需氨基酸,广泛应用于医药、食品与饲料等行业.工业上采用的色氨酸生产方法有化学合成法、转化法及微生物发酵法.近年来,随着代谢工程在色氨酸菌种选育中的成功运用,微生物发酵法逐渐成为主要的色氨酸生产方法.系统综述了微生物发酵法生产色氨酸所涉及的代谢工程策略,包括生物合成色氨酸的代谢调控机制以及途径...     

Physiology of microbial cells and metabolic engineering

This review is devoted to the problems of the physiology and cell biology of microorganisms in relation to metabolic engineering. The latter is considered as a branch of fundamental and applied biotechnology aimed at controlling microbial metabolism by methods of genetic engineering and classical genetics and based on intimate knowledge of cell metabolism. Attention is also given to the problems associated with the metabolic limitation of microbial biosyntheses, analysis and control of metabolic fluxes, rigidity of metabolic pathways, the role of pleiotropic (global) regulatory systems in the control of metabolic fluxes, and prospects of physiological and evolutionary approaches in metabolic engineering.     

Quorum sensing-based metabolic engineering of the precursor supply in Streptomyces coelicolor to improve heterologous production of neoaureothin

Streptomyces are important industrial bacteria that produce pharmaceutically valuable polyketides. However, mass production on an industrial scale is limited by low productivity, which can be overcome through metabolic engineering and the synthetic biology of the host strain. Recently, the introduction of an auto-inducible expression system depending on microbial physiological state has been suggested as an important tool for the industrial-scale production of polyketides. In this study, titer improvement by enhancing the pool of CoA-derived precursors required for polyketide production was driven in a quorum sensing (QS)-dependent manner. A self-sustaining and inducer-independent regulatory system, named the QS-based metabolic engineering of precursor pool (QMP) system, was constructed, wherein the expression of genes involved in precursor biosynthesis was regulated by the QS-responsive promoter, scbAp. The QMP system was applied for neoaureothin production in a heterologous host, Streptomyces coelicolor M1152, and productivity increased by up to 4-fold. In particular, the engineered hyperproducers produced high levels of neoaureothin without adversely affecting cell growth. Overall, this study showed that self-regulated metabolic engineering mediated by QS has the potential to engineer strains for polyketide titer improvement.     

Opportunities for yeast metabolic engineering: Lessons from synthetic biology

Constant progress in genetic engineering has given rise to a number of promising areas of research that facilitated the expansion of industrial biotechnology. The field of metabolic engineering, which utilizes genetic tools to manipulate microbial metabolism to enhance the production of compounds of interest, has had a particularly strong impact by providing new platforms for chemical production. Recent developments in synthetic biology promise to expand the metabolic engineering toolbox further by creating novel biological components for pathway design. The present review addresses some of the recent advances in synthetic biology and how these have the potential to affect metabolic engineering in the yeast Saccharomyces cerevisiae. While S. cerevisiae for years has been a robust industrial organism and the target of multiple metabolic engineering trials, its potential for synthetic biology has remained relatively unexplored and further research in this field could strongly contribute to industrial biotechnology. This review also addresses are general considerations for pathway design, ranging from individual components to regulatory systems, overall pathway considerations and whole-organism engineering, with an emphasis on potential contributions of synthetic biology to these areas. Some examples of applications for yeast synthetic biology and metabolic engineering are also discussed.     

Applications of metabolic modeling to drive bioprocess development for the production of value-added chemicals

Increasing numbers of value added chemicals are being produced using microbial fermentation strategies. Computational modeling and simulation of microbial metabolism is rapidly becoming an enabling technology that is driving a new paradigm to accelerate the bioprocess development cycle. In particular, constraint-based modeling and the development of genome-scale models of industrial microbes are finding increasing utility across many phases of the bioprocess development workflow. Herein, we review and discuss the requirements and trends in the industrial application of this technology as we build toward integrated computational/experimental platforms for bioprocess engineering. Specifically we cover the following topics: (1) genome-scale models as genetically and biochemically consistent representations of metabolic networks; (2) the ability of these models to predict, assess, and interpret metabolic physiology and flux states of metabolism; (3) the model-guided integrative analysis of high throughput ‘omics’ data; (4) the reconciliation and analysis of on- and off-line fermentation data as well as flux tracing data; (5) model-aided strain design strategies and the integration of calculated biotransformation routes; and (6) control and optimization of the fermentation processes. Collectively, constraint-based modeling strategies are impacting the iterative characterization of metabolic flux states throughout the bioprocess development cycle, while also driving metabolic engineering strategies and fermentation optimization.     

Metabolic engineering for the utilization of carbohydrate portions of lignocellulosic biomass

The petrochemical industry has grown to meet the need for massive production of energy and commodities along with an explosive population growth; however, serious side effects such as greenhouse gas emissions and global warming have negatively impacted the environment. Lignocellulosic biomass with myriad quantities on Earth is an attractive resource for the production of carbon-neutral fuels and chemicals through environmentally friendly processes of microbial fermentation. This review discusses metabolic engineering efforts to achieve economically feasible industrial production of fuels and chemicals from microbial cell factories using the carbohydrate portion of lignocellulosic biomass as substrates. The combined knowledge of systems biology and metabolic engineering has been applied to construct robust platform microorganisms with maximum conversion of monomeric sugars, such as glucose and xylose, derived from lignocellulosic biomass. By comprehensively revisiting carbon conversion pathways, we provide a rationale for engineering strategies, as well as their features, feasibility, and recent representative studies. In addition, we briefly discuss how tools in systems biology can be applied in the field of metabolic engineering to accelerate the development of microbial cell factories that convert lignocellulosic biomass into carbon-neutral fuels and chemicals with economic feasibility.     

Engineering of microorganisms for the production of biofuels and perspectives based on systems metabolic engineering approaches

The increasing oil price and environmental concerns caused by the use of fossil fuel have renewed our interest in utilizing biomass as a sustainable resource for the production of biofuel. It is however essential to develop high performance microbes that are capable of producing biofuels with very high efficiency in order to compete with the fossil fuel. Recently, the strategies for developing microbial strains by systems metabolic engineering, which can be considered as metabolic engineering integrated with systems biology and synthetic biology, have been developed. Systems metabolic engineering allows successful development of microbes that are capable of producing several different biofuels including bioethanol, biobutanol, alkane, and biodiesel, and even hydrogen. In this review, the approaches employed to develop efficient biofuel producers by metabolic engineering and systems metabolic engineering approaches are reviewed with relevant example cases. It is expected that systems metabolic engineering will be employed as an essential strategy for the development of microbial strains for industrial applications.     

反义RNA技术在丝状真菌代谢工程中的应用

丝状真菌作为一种重要的工业微生物,采用各种表达调控技术对其代谢途径进行改造以便适应生产需求成为当前的研究热点之一。反义RNA技术是代谢工程中调控基因表达的一种重要手段,且由于其操作简单避免了基因敲除技术的复杂性,在丝状真菌体系中有着良好的应用前景。本综述中,从反义RNA的作用机理、真菌体系的基因工程技术以及目前反义RNA技术的应用等方面,对反义RNA技术在丝状真菌代谢工程中的应用进行了概述。     

Engineering microbes for isoprene production

Isoprene is facing a growing global market due to its wide industrial applications. Current industrial production of isoprene is almost entirely petroleum-based, which is influenced by the shrinking C5 supply, while the natural emission of isoprene is predominantly contributed by plants. To bridge the need gap, a highly efficient fermentation-based process for isoprene production might be a suitable and sustainable solution, and extensive research works have been performed to achieve this goal. Here we review the accomplishments in this field by summarizing the history and prospects of microbial isoprene production. The natural producers and biosynthesis pathways of isoprene, the key enzyme isoprene synthase and the metabolic engineering strategies adopted for developing isoprene-producing microorganisms are introduced. In particular, strategies employed for achieving engineered strains with improved performance indices are discussed based on the published papers and patents. The perspectives on further performance improvements and potential future strategies are presented as well.