利用基因工程改良植物类胡萝卜素的合成

类胡萝卜素(carotenoids)是植物体内存在的一类重要天然色素物质的总称,其生物功能广泛.类胡萝卜素是人类饮食结构中重要的组成部分,并且在医药、化妆品及食品与饲料工业等方面扮演着重要的角色.类胡萝卜素还是一些维生素合成的前体,具有多种保健功能,可以提高人体免疫力,并具有抗癌的功效.目前有大量关于提高植物体内类胡萝卜素含量及定向改变其种类的研究,对类胡萝卜素代谢途径及其调控的理解是这些研究的基础.主要阐述植物天然类胡萝卜素的生物合成及利用基因工程对类胡萝卜素改良的研究进展.     

合成微生物技术促进类胡萝卜素产品的高效合成

类胡萝卜素是一类重要的天然色素,因其具有多种生物功效,应用非常广泛。首先对类胡萝卜素的天然合成途径进行了介绍,总结了类胡萝卜素相关产品应用及目前的生产方式,着重介绍了番茄红素、β-胡萝卜素和虾青素等产品微生物发酵法的制备方法在菌株和途径构建上的最新研究成果。重点对类胡萝卜素生物合成产业化面临的主要问题进行了分析讨论,并提出一些建议供相关产业进行参考。     

植物类胡萝卜素提取与分析技术研究进展

类胡萝卜素是所有光合生物及一些非光合原核生物和真菌合成的亲脂性天然色素, 对植物、动物和人都具有广泛的生物学作用。随着现代分析技术的快速发展, 越来越多的类胡萝卜素得以发现和利用。该文通过对植物类胡萝卜素的提取、分离纯化、含量测定和结构鉴定等方面的最新研究进展进行系统阐述, 以期为植物类胡萝卜素的有效开发利用提供技术支撑。     

圆红冬孢酵母基因编辑及天然产物合成的研究进展

圆红冬孢酵母(Rhodotorula toruloides)是一种能够天然合成多种类胡萝卜素和油脂的非模式酵母。该菌能够利用各种廉价原料,耐受甚至同化利用多种有毒木质纤维素水解副产物。目前,该酵母被广泛用于微生物油脂、萜烯类化合物、各种高价值酶、糖醇和聚酮化合物的生产研究。鉴于其广阔的工业应用前景,研究人员对其开展了多维度的理论和技术的探索,包括基因组、转录组、蛋白组、遗传操作平台等。本文着重阐述近年来圆红冬孢酵母的代谢工程和天然产物合成的研究进展,并展望其细胞工厂构建中面临的挑战和可能的应对决策。     

放线菌天然产物糖基化改造研究进展

放线菌可以产生结构多样的天然产物, 其中包括很多重要的抗菌和抗肿瘤药物。糖基化修饰在天然产物中广泛存在, 糖基侧链的变化往往会影响天然产物的生物活性。本文综述了放线菌来源天然产物糖基化改造的研究进展。糖基侧链改造的方法主要分为体内基因工程和体外酶学法。运用这两种方法已经成功对多种天然产物进行了糖基侧链改造, 获得了大量带有新糖基修饰的天然产物, 其中有些生物活性得以提高。天然产物糖基侧链改造为新药开发提供了一个重要的途径。     

胭脂素的生物合成及应用研究进展

由于合成色素对人类健康具有潜在危害,天然色素逐渐受到青睐.胭脂素作为类胡萝卜素物质是世界第二大天然色素,其生物合成途径是国际研究热点,目前尚未被完整解析.文中综述了胭脂素的化学特性与提取方法、合成途径研究及应用现状,比较传统提取方法与新提取技术的特点,阐述胭脂素合成通路相关基因及非生物胁迫对合成通路的影响,介绍胭脂素在...     

抗单纯疱疹病毒的天然产物研究现况

单纯疱疹病毒(HSV)是一种发病率极高,在全世界分布广泛的疱疹病毒,易引起多种人类皮肤疾病,严重危害人类的身体健康和生命安全。目前临床上常用核苷类抗病毒药物对单纯疱疹病毒感染进行治疗,但存在着许多明显的缺点,如：生物利用度低,溶解度小,临床多见不良反应且容易导致病毒耐药等。与核苷抗病毒药物相比,天然产物具有作用时间长、低毒、病毒不易产生耐药性等显著优点。随着对天然产物研究的深入,大量研究和实验证明：从植物或动物中提取的天然产物对于单纯疱疹病毒感染的治疗有着广阔的前景,天然产物成了寻找新型抗疱疹病毒药物的重要来源。将对近年来天然产物抗HSV研究状况进行整理、总结和分析,为将来天然产物抗HSV感染研究提供参考和对比。     

非天然氨基酸及非天然蛋白合成的研究进展

非天然氨基酸是天然氨基酸的衍生物,其具有重要的生理和药理功能.由非天然氨基酸合成的非天然蛋白同样具有特别的功能与活性.非天然氨基酸插入蛋白质中的研究为新型生物材料和蛋白质药物等的合成和应用提供了新的指导方向.基于此,本文综述了非天然氨基酸的生物合成方法,分析了非天然氨基酸生物合成目前存在的难点,总结了非天然氨基酸插入蛋...     

代谢工程改造解脂耶氏酵母合成植物萜类化合物的研究进展

萜类化合物是一类广泛存在于植物中的天然产物,其在食品、药品和化工等多个领域中均有广泛的用途,市场潜力巨大.因此,开发生产萜类化合物等植物天然产物可再生的微生物资源来补充甚至代替原有稀少和珍贵的植物资源,具有重要的理论意义和潜在的应用价值.解脂耶氏酵母是目前使用最广泛的非常规酵母底盘细胞之一.近年来,利用代谢工程及合成生...     

微生物源天然防腐剂在食品上的应用研究

微生物源天然防腐剂是理想的天然食品防腐剂,具有安全、无毒、高效、无副作用的特点,符合未来食品防腐的发展与使用要求,在食品工业中的应用越来越广泛.该文对天然微生物源防腐剂的来源分类、抑菌特性、抑菌机理及适用范围进行了系统的研究分析与论述.有针对性地对目前两种应用最为广泛的微生物源天然防腐剂乳酸链球菌素和纳他霉素予以介绍,同时对微生物源天然防腐剂使用过程中遇到的问题提出了对策建议.对天然防腐剂的应用与发展具有现实和指导意义.     

Metabolic engineering of carotenoid biosynthesis in plants

Carotenoids are one of the most diverse classes of natural compounds. Plant carotenoids are composed of a C40 isoprenoid skeleton with or without epoxy, hydroxy and keto groups. They have fundamental roles in human nutrition as antioxidants and vitamin A precursors and their consumption is increasingly associated with protection from a range of diseases. They are also used commercially as safe food, feed and cosmetic colorants and they protect plants from photooxidative stress. In the past six years many metabolic engineering efforts have been undertaken in plants aiming to improve the nutritional value of staple crops, to enable the use of plants as 'cell factories' for producing specialty carotenoids and to improve plant resistance to abiotic stress.     

Structure and function of the genes involved in the biosynthesis of carotenoids in the mucorales

Carotenoids are widely distributed natural pigments which are in an increasing demand by the market, due to their applications in the human food, animal feed, cosmetics, and pharmaceutical industries. Although more than 600 carotenoids have been identified in nature, only a few are industrially important (β-carotene, astaxanthin, lutein or lycopene). To date chemical processes manufacture most of the carotenoid production, but the interest for carotenoids of biological origin is growing since there is an increased public concern over the safety of artificial food colorants. Although much interest and effort has been devoted to the use of biological sources for industrially important carotenoids, only the production of biological β-carotene and astaxanthin has been reported. Among fungi, several Mucorales strains, particularlyBlakeslea trispora, have been used to develop fermentation process for the production of β-carotene on almost competitive cost-price levels. Similarly, the basidiomycetous yeastXanthophyllomyces dendrorhous (the perfect state ofPhaffia rhodozyma), has been proposed as a promising source of astaxanthin. This paper focuses on recent findings on the fungal pathways for carotenoid production, especially the structure and function of the genes involved in the biosynthesis of carotenoids in the Mucorales. An outlook of the possibilities of an increased industrial production of carotenoids, based on metabolic engineering of fungi for carotenoid content and composition, is also discussed.     

A Review of the Chemistry and Biological Activities of Natural Colorants,Dyes, and Pigments: Challenges,and Opportunities for Food,Cosmetics, and Pharmaceutical Application

Natural pigments are important sources for the screening of bioactive lead compounds. This article reviewed the chemistry and therapeutic potentials of over 570 colored molecules from plants, fungi, bacteria, insects, algae, and marine sources. Moreover, related biological activities, advanced extraction, and identification approaches were reviewed. A variety of biological activities, including cytotoxicity against cancer cells, antioxidant, anti-inflammatory, wound healing, anti-microbial, antiviral, and anti-protozoal activities, have been reported for different pigments. Considering their structural backbone, they were classified as naphthoquinones, carotenoids, flavonoids, xanthones, anthocyanins, benzotropolones, alkaloids, terpenoids, isoprenoids, and non-isoprenoids. Alkaloid pigments were mostly isolated from bacteria and marine sources, while flavonoids were mostly found in plants and mushrooms. Colored quinones and xanthones were mostly extracted from plants and fungi, while colored polyketides and terpenoids are often found in marine sources and fungi. Carotenoids are mostly distributed among bacteria, followed by fungi and plants. The pigments isolated from insects have different structures, but among them, carotenoids and quinone/xanthone are the most important. Considering good manufacturing practices, the current permitted natural colorants are: Carotenoids (canthaxanthin, β-carotene, β-apo-8′-carotenal, annatto, astaxanthin) and their sources, lycopene, anthocyanins, betanin, chlorophyllins, spirulina extract, carmine and cochineal extract, henna, riboflavin, pyrogallol, logwood extract, guaiazulene, turmeric, and soy leghemoglobin.     

Differences in carotenoid composition among hymenobacter and related strains support a tree-like model of carotenoid evolution

Carotenoids are structurally diverse pigments of biotechnological interest as natural colorants and in the prevention of human disease. The carotenoids present in 19 strains taxonomically related to the poorly described, nonphotosynthetic bacterial genus Hymenobacter, including 10 novel isolates cultivated from Victoria Upper Glacier, Antarctica, were characterized using high-performance liquid chromatography (HPLC). Nine chemically distinct carotenoids, present in various combinations irresolvable by conventional crude spectrophotometric analyses, were purified by preparative HPLC and characterized using UV-visible light absorption spectroscopy and high-resolution mass spectrometry. All major Hymenobacter carotenoids appear to be derived from a common backbone of 2'-hydroxyflexixanthin and include previously unreported presumptive hexosyl, pentosyl, and methyl derivatives. Their distribution does not, however, correlate perfectly with 16S rRNA gene phylogeny. Carotenoid composition, therefore, may be strain specific and does not follow a strictly homogeneous pattern of vertical evolutionary descent.     

An update on microbial carotenoid production: application of recent metabolic engineering tools

Carotenoids are ubiquitous pigments synthesized by plants, fungi, algae, and bacteria. Industrially, carotenoids are used in pharmaceuticals, neutraceuticals, and animal feed additives, as well as colorants in cosmetics and foods. Scientific interest in dietary carotenoids has increased in recent years because of their beneficial effects on human health, such as lowering the risk of cancer and enhancement of immune system function, which are attributed to their antioxidant potential. The availability of carotenoid genes from carotenogenic microbes has made possible the synthesis of carotenoids in non-carotenogenic microbes. The increasing interest in microbial sources of carotenoid is related to consumer preferences for natural additives and the potential cost effectiveness of creating carotenoids via microbial biotechnology. In this review, we will describe the recent progress made in metabolic engineering of non-carotenogenic microorganisms with particular focus on the potential of Escherichia coli for improved carotenoid productivity. Amitabha Das and Sang-Hwal Yoon contributed equally to this work.     

Progress in Microbial Carotenoids Production

Carotenoids are versatile isoprenoids pigments, play a vital role in the cellular system, starting from antioxidant to gene regulation. Carotenoids are widely used in food, nutraceuticals, and cosmetics owing to their vitamin A, antioxidant and anticancer activities. The demand of carotenoids in various sectors has triggered the research to explore a commercially viable and environmentally friendly production. This article presents a short review of progress in carotenoids production from microbial platforms.     

Sequencing and phylogenetic analyses of talaromyces amestolkiae from amazon: A producer of natural colorants

The population interest in health products is increasing day-by-day. Thus, the demand for natural products to be added in food and pharmaceutical commodity is also rising. Among these additives, colorants, which provides color to products, can be produced by microorganism through bioprocess. Looking for new source of natural colorants, fungi have been employed to this purpose producing novel and safer natural colorants. So, the main goal of this study was to describe a Talaromyces species able to produce natural colorants and investigate nutritional parameters of colorants production using statistical tool. The taxonomy classified the microorganism as Talaromyces amestolkiae. The statistical design evaluated pH and glucose, meat extract and meat peptone concentration as independent variables, and red colorants production as main response. Under the best condition (g/L: glucose 30, meat extract 1, meat peptone 10, and initial pH of 7.0) an increase of 229% in the red colorant production was achieved as compared with the initial media used. The dried fermented broth containing red colorants showed low cytotoxicity against fibroblasts cells (IC₅₀ > 187.5 g/L) and effective antimicrobial activity against S. aureus (MIC of 2.5 g/L). Thus, T. amestolkiae colorants can be attractive to food and pharmaceutical applications as it does not produce toxic compounds and can promote protection against microorganism contaminants. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2684, 2019     

Metabolic engineering towards biotechnological production of carotenoids in microorganisms

Carotenoids are important natural pigments produced by many microorganisms and plants. Traditionally, carotenoids have been used in the feed, food and nutraceutical industries. The recent discoveries of health-related beneficial properties attributed to carotenoids have spurred great interest in the production of structurally diverse carotenoids for pharmaceutical applications. The availability of a considerable number of microbial and plant carotenoid genes that can be functionally expressed in heterologous hosts has opened ways for the production of diverse carotenoid compounds in heterologous systems. In this review, we will describe the recent progress made in metabolic engineering of non-carotenogenic microorganisms for improved carotenoid productivity. In addition, we will discuss the application of combinatorial and evolutionary strategies to carotenoid pathway engineering to broaden the diversity of carotenoid structures synthesized in recombinant hosts.     

Transcript profiling of genes involved in carotenoid biosynthesis among three carrot cultivars with various taproot colors

Protoplasma - Carotenoids are a group of natural pigments that are widely distributed in various plants. Carrots are plants rich in carotenoids and have fleshy roots with different colors....