The genus Gluconobacter oxydans: comprehensive overview of biochemistry and biotechnological applications

The genus Gluconobacter comprises some of the most frequently used microorganisms when it comes to biotechnological applications. Not only has it been involved in "historical" production processes, such as vinegar production, but in the last decades many bioconversion routes for special and rare sugars involving Gluconobacter have been developed. Among the most recent are the biotransformations involved in the production of L-ribose and miglitol, both very promising pharmaceutical lead molecules. Most of these processes make use of Gluconobacter's membrane-bound polyol dehydrogenases. However, recently other enzymes have also caught the eye of industrial biotechnology. Among them are dextran dextrinase, capable of transglucosylating substrate molecules, and intracellular NAD-dependent polyol dehydrogenases, of interest for co-enzyme regeneration. As such, Gluconobacter is an important industrial microbial strain, but it also finds use in other fields of biotechnology, such as biosensor-technology. This review aims to give an overview of the myriad of applications for Gluconobacter, with a special focus on some recent developments.     

Current status in biotechnological production and applications of glycolipid biosurfactants

Biosurfactants are natural compounds with surface activity and emulsifying properties produced by several types of microorganisms and have been considered an interesting alternative to synthetic surfactants. Glycolipids are promising biosurfactants, due to low toxicity, biodegradability, and chemical stability in different conditions and also because they have many biological activities, allowing wide applications in different fields. In this review, we addressed general information about families of glycolipids, rhamnolipids, sophorolipids, mannosylerythritol lipids, and trehalose lipids, describing their chemical and surface characteristics, recent studies using alternative substrates, and new strategies to improve of production, beyond their specificities. We focus in providing recent developments and trends in biotechnological process and medical and industrial applications.     

植物病毒资源属性和应用基础研究进展

病毒作为地球上最简单的生命形式,通过感染人、动物和植物等寄主产生传染性疾病。与其他微生物相比,病毒具有基因组小、复制量大、遗传操作简单等特点,具有很强的生物资源属性。过去几十年,对植物病毒的研究主要集中于解析其致病机制、植物的抗性机制及如何防控植物病害。但是随着研究的深入及概念的革新,人们发现植物病毒还具有很强的生物资源属性。随着分子生物学以及基因组、转录组、蛋白组学等技术的发展,越来越多的植物病毒被发现、改造和利用。本综述着重围绕植物病毒的资源属性与病毒载体的改造利用及其在生物工程方面的应用等最新研究进展,讨论其广泛的应用前景,挖掘其资源化的潜力。     

The brown seaweed genus Zonaria: major features,biotechnological potential,and applications

Journal of Applied Phycology - This review is a broad overview of species of the genus Zonaria, a relevant taxonomic grouping within the brown algae, considering data regarding the most common...     

Agar and agarose biotechnological applications

Agar, a phycocolloid obtained commercially from species of Gelidium and Gracilaria, has been known for several centuries; its earliest industrial application was in the preparation of solid microbiological media. The numerous techniques available for the purification of agar affect the characteristics of bacterial-grade agar. The availability of agarose, that fraction of agar with the lowest possible charge, has enhanced the utilzation of this phycocolloid. The process of gelation of agarose is discussed and the applications of agarose gels in different types of chromatography are summarized. Agarose has many and diverse important applications in biotechnology. These uses, and newly-developed ones, can be expected to increase the demands for high-quality agarose in the rapidly expanding field of biotechnology.     

Evaluation of the antibiotic biosynthetic potential of the genus Amycolatopsis and description of Amycolatopsis circi sp. nov., Amycolatopsis equina sp. nov. and Amycolatopsis hippodromi sp. nov

Aims: To describe three new Amycolatopsis strains and assess the antibiotic biosynthetic potential of the genus. Methods and Results: Three strains, designated S1·3^T, S3·6^T and SE(8)3^T, belonging to the genus Amycolatopsis were isolated and found to cluster together by 16S rRNA and gyrB gene‐based phylogenetic analysis. Genetic distance values, based on the gyrB gene, were calculated between the strains and their closest relatives and were all above the threshold value of 0·02 that has been proposed to distinguish Amycolatopsis type strains. DNA–DNA hybridization experiments against related type strains confirmed that strain S3·6^T represents a unique genomic species. Strain S3·6^T was also found to be distinct from strains S1·3^T and SE(8)3^T, the latter two of which were also shown to be distinct from each other. Antibiotic biosynthetic genes were identified from multiple Amycolatopsis strains, and their presence was found to be phylogenetically associated. Conclusions: The data presented in this study indicate that strains S1·3^T, SE(8)3^T and S3·6^T belong to three novel species, for which the names Amycolatopsis circi sp. nov. (= DSM 45561^T = NRRL B‐24841^T), Amycolatopsis equina sp. nov. (= DSM 45563^T = NRRL B‐24842^T) and Amycolatopsis hippodromi sp. nov. (= DSM 45562^T = NRRL B‐24843^T) are proposed. Significance and Impact of the Study: Three new species of Amycolatopsis are described, and the knowledge of the antibiotic biosynthetic potential of the genus has been extended.     

DNA polymerases and biotechnological applications

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Cellulose-binding domains: biotechnological applications

Many researchers have acknowledged the fact that there exists an immense potential for the application of the cellulose-binding domains (CBDs) in the field of biotechnology. This becomes apparent when the phrase "cellulose-binding domain" is used as the key word for a computerized patent search; more then 150 hits are retrieved. Cellulose is an ideal matrix for large-scale affinity purification procedures. This chemically inert matrix has excellent physical properties as well as low affinity for nonspecific protein binding. It is available in a diverse range of forms and sizes, is pharmaceutically safe, and relatively inexpensive. Present studies into the application of CBDs in industry have established that they can be applied in the modification of physical and chemical properties of composite materials and the development of modified materials with improved properties. In agro-biotechnology, CBDs can be used to modify polysaccharide materials both in vivo and in vitro. The CBDs exert nonhydrolytic fiber disruption on cellulose-containing materials. The potential applications of "CBD technology" range from modulating the architecture of individual cells to the modification of an entire organism. Expressing these genes under specific promoters and using appropriate trafficking signals, can be used to alter the nutritional value and texture of agricultural crops and their final products.     

Perspectives on biotechnological applications of archaea

Many archaea colonize extreme environments. They include hyperthermophiles, sulfur-metabolizing thermophiles, extreme halophiles and methanogens. Because extremophilic microorganisms have unusual properties, they are a potentially valuable resource in the development of novel biotechnological processes. Despite extensive research, however, there are few existing industrial applications of either archaeal biomass or archaeal enzymes. This review summarizes current knowledge about the biotechnological uses of archaea and archaeal enzymes with special attention to potential applications that are the subject of current experimental evaluation. Topics covered include cultivation methods, recent achievements in genomics, which are of key importance for the development of new biotechnological tools, and the application of wild-type biomasses, engineered microorganisms, enzymes and specific metabolites in particular bioprocesses of industrial interest.     

Current biotechnological developments in Belgium

In recent years, actions have been undertaken by the Belgian government to promote process innovation and technical diversification. Research programs are initiated and coordinated by the study committee for biotechnology setup within the Institute for Scientific Research in Industry and Agriculture (IRSIA). As a result of this action, the main areas where biotechnological processes are developed or commercially exploited include plant genetics, protein engineering, hybridoma technology, biopesticides, production by genetic engineering of vaccines and drugs, monoclonal detection of human and animal deseases, process reactors for aerobic and anaerobic wastewater treatment, and genetic modification of yeast and bacteria as a base for biomass and energy. Development research also includes new fermentation technologies principally based on immobilization of microorganisms, reactor design, and optimization of unit operations involved in downstream processing. Food, pharmaceutical, and chemical industries are involved in genetic engineering and biotechnology and each of these sectors is overviewed in this paper.     

Current biotechnological developments in Thailand

Thailand is very much aware of the potential and the opportunities in biotechnology and has given the utmost effort into the development of biotechnology. In 1983, the government has set up the National Center for Genetic Engineering and Biotechnology (NCGEB). The center operates through a network of research institutes and laboratories in order to maximize and consolidate the limited resources of the country. The center also plays a key role in formulating policies and plans relating to biotechnology as well as in supporting and coordinating biotechnology research and development. A sum of U.S. $8.6 million has been allocated for an initial 5-year program for R D & E activities. The priority consideration is on utilizing various levels of biotechnology for improvement in agriculture, industrial productivity, health, and environment. To facilitate and strengthen the link between research institutions and the private sector, the high-level Science and Technology Development Board (STDB) was established in 1986, with an initial allocation of U.S. $2.9 million between 1986 to 1992 for biotechnology. At present, there are between 400 to 500 scientists and technologists with M.S. or higher degrees actively working in research and development (R & D) in biotechnology and engineering, mostly in universities and government research laboratories. It is expected that approximately 500 graduates with advanced degrees in biotechnology and related fields will be produced during the 5-year plan (1987 to 1991).     

Archaeal lipids and their biotechnological applications

The lipids of Archaea, based on glycerol isopranoid ethers, can be used taxonomically to distinguish between phenotypic subgroups of the domain to delineate them clearly from all other organisms. This review is a general survey of the structural features of archaeal lipids and how they relate to survival in the harsh environments in which the Archaea live. The molecular organization of archaeal lipids in monolayers, artificial black membranes and vesicles and the unique properties and possible biotechnological applications of liposomes of the lipids are presented. The results with these liposomes are compared with similar data obtained with synthetic compounds which mimic the structure of archaeal lipids. Studies on computer simulation are also reported.A. Gambacorta is with the istituto per la Chimica di Molecole di interesse Biologico, CNR via Toiano 6, 80072 Arco Felice, Napoli, Italy; A Gliozzi is with the Dipartimento di Fisica, Università di Genova, via Dodecanneso 33, 16146 Genova, Italy. M. De Rosa is with the Istituto di Biochimica delle Macromolecole. Seconda Università di Napoli, via Costantinopoli 16, 80132 Napoli, Italy.     

Recombinant microbial lipases for biotechnological applications

Lipases, mainly of microbial origin, represent the most widely used class of enzymes in biotechnological applications and organic chemistry. Modern methods of genetic engineering combined with an increasing knowledge of structure and function will allow further adaptation to industrial needs and exploration of novel applications. Production of such tailored lipases requires their functional overexpression in a suitable host. Hence, this article describes the functional heterologous production of commercially important microbial lipases. Based on the knowledge of different lipases' substrate binding sites, the most suitable lipase for a particular application may be selected.     

Gluconobacter oxydans: its biotechnological applications

Gluconobacter oxydans is a gram-negative bacterium belonging to the family Acetobacteraceae. G. oxydans is an obligate aerobe, having a respiratory type of metabolism using oxygen as the terminal electron acceptor. Gluconobacter strains flourish in sugary niches e.g. ripe grapes, apples, dates, garden soil, baker's soil, honeybees, fruit, cider, beer, wine. Gluconobacter strains are non-pathogenic towards man and other animals but are capable of causing bacterial rot of apples and pears accompanied by various shades of browning. Several soluble and particulate polyol dehydrogenases have been described. The organism brings about the incomplete oxidation of sugars, alcohols and acids. Incomplete oxidation leads to nearly quantitative yields of the oxidation products making G. oxydans important for industrial use. Gluconobacter strains can be used industrially to produce L-sorbose from D-sorbitol; D-gluconic acid, 5-keto- and 2-ketogluconic acids from D-glucose; and dihydroxyacetone from glycerol. It is primarily known as a ketogenic bacterium due to 2,5-diketogluconic acid formation from D-glucose. Extensive fermentation studies have been performed to characterize its direct glucose oxidation, sorbitol oxidation, and glycerol oxidation. The enzymes involved have been purified and characterized, and molecular studies have been performed to understand these processes at the molecular level. Its possible application in biosensor technology has also been worked out. Several workers have explained its basic and applied aspects. In the present paper, its different biotechnological applications, basic biochemistry and molecular biology studies are reviewed.     

Harnessing lignin evolution for biotechnological applications

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Structure and biotechnological applications of odorant-binding proteins

Odorant-binding proteins (OBPs) are small soluble polypeptides found in sensory organs of vertebrates and insects as well as in secretory glands and are dedicated to detection and release of chemical stimuli. OBPs of vertebrates belong to the family of lipocalin proteins, while those of insects are folded into α-helical domains. Both types of architectures are extremely stable to temperature, organic solvents and proteolytic digestion. These characteristics make OBPs suitable elements for fabricating biosensors to be used in the environment, as well as for other biotechnological applications. The affinity of OBPs for small volatile organic compounds is in the micromolar range, and they have broad specificity to a range of ligands. For biotechnological applications, OBPs can be expressed in bacterial systems at low cost and are easily purified. The large amount of information available on their structures and affinities to different molecules should allow the design of specific mutants with desired characteristics and represent a solid base for tailoring OBPs for different applications.     

Engineering of staphylococcal surfaces for biotechnological applications

Novel surface proteins can be introduced onto bacterial cell surfaces by recombinant means. Here, we describe various applications of two such display systems for the food-grade bacteria Staphylococcus carnosus and Staphylococcus xylosus, respectively. The achievements in the use of such staphylococci as live bacterial vaccine delivery vehicles will be described. Co-display of proteins and peptides with adhesive properties to enable targeting of the bacteria, have significantly improved the vaccine delivery potential. Recently, protective immunity to respiratory syncytial virus (RSV) could be evoked in mice by intranasal immunization using such 'second generation' vaccine delivery systems. Furthermore, antibody fragments and other 'affinity proteins' with capacity to specifically bind a certain protein, e.g. Staphylococcus aureus protein A-based affibodies, have been surface-displayed on staphylococci as initial efforts to create whole-cell diagnostic devices. Surface display of metal-binding peptides, or protein domains into which metal binding properties has been engineered by combinatorial protein engineering, have been exploited to create staphylococcal bioadsorbents for potential environmental or biosensor applications. The use of these staphylococcal surface display systems as alternatives for display of large protein libraries and subsequent affinity selection of relevant binding proteins by fluorescence-activated cell sorting (FACS) will be discussed.