bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microcarrier Culture
Authors: Sharfstein Susan T. , Kaisermayer Christian 
Published: April 2010

AbstractMicrocarrier culture provides an easily scalable approach to culture of anchorage‐dependent mammalian cells, providing a much higher surface area‐to‐volume ratio compared with roller bottles or flat layer cultivation systems. Microcarriers are also useful for the production of recombinant proteins, particularly to facilitate cell retention in cases where perfusion would be advantageous, for example, low specific productivity or unstable products. Microcarriers provide the cultivation surface that is necessary for adherent cells, and macroporous carriers can be used to immobilize suspension cells. In this review of microcarrier culture, we discuss the history of microcarrier use, strategies for optimal development of microcarrier‐based processes, the use of microcarriers for viral vaccine and recombinant protein production, and new biomedical applications for microcarriers, including tissue engineering, stem‐cell culture, andin vitrotoxicology.
Micropropagation of Plants
Authors: Loberant Beth , Altman Arie 
Published: April 2010

AbstractMicropropagation (or in vitro propagation) is the most common term used for clonal, true‐to‐type propagation of plants by a variety of tissue, cell and organ culture methods. It implies the aseptic culture of small sections (i.e., explants) of tissues and organs, in closed vessels with defined culture media and under controlled environmental conditions. Micropropagation, in addition to genetic engineering, is at present the most commercially efficient and practically‐oriented plant biotechnology, resulting in rapid generation of a large number of clonal plants of many plant species, which are in many cases also virus‐ or other pathogen‐free. It is now the technical link in the generation of transgenic plants and somatically‐bred plants.Following a brief history and a presentation of the objectives of micropropagation and related applications, we discuss the basic biological principles of micropropagation, including totipotency of plant cells, cell division and callus formation, and the major forms of differentiation and regeneration (axillary bud proliferation, organogenesis, and somatic embryogenesis). The practice of micropropagation is dependent on precise implementation of several technical aspects and developmental/growth stages, including the use of proper explants, asepsis (axenic culture), culture media composition and use of appropriate growth vessels, and the monitoring and control of macro‐ and micro‐environmental conditions within the laboratory and acclimatization facility. We include a review of the design and maintenance of the laboratory and further discuss the advantages and disadvantages of micropropagation and the organizational, economic and financial aspects of commercial micropropagation. In addition, we address critical limiting factors such as recalcitrance, somatic variation and trueness‐to‐type, and contamination. New trends in improving the efficiency of micropropagation conclude this chapter.
Monoclonal Antibody Production, Cell Lines
Authors: Markusen Julia F. , Robinson David K. 
Published: April 2010

AbstractProduction of recombinant antibodies begins with construction of the cell line that will be used for expression of the final monoclonal antibody (MAb) product. There are many steps downstream of cell line construction for ensuring safety, efficacy, quality, productivity, and regulatory acceptability; however, consideration of these attributes at the point of cell line selection is critical. Each of these important features can be greatly influenced by the choice of the host system. The product quality attribute most likely to be influenced by the cell line chosen for manufacture of a MAb is glycosylation. Rather than producing a highly homogeneous oligosaccharide structure, most host cell lines produce antibody with an array of different oligosaccharide structures. In addition, these structures may contain immunogenic, nonhuman forms potentially affecting the safety and efficacy of the product. All of the MAbs currently licensed in the United States are produced in two mammalian cell lines, hamster or murine. Mammalian cell line expression vectors and selection methods have been optimized to generate highly productive systems. To date, there are no approved therapeutic MAbs in the United States that are produced in human, fungal, bacterial or transgenic systems. However, advances in genetic engineering of these host cell systems to control oligosaccharide structures and regulatory acceptance for production of other therapeutic proteins in these alternative host platforms warrant consideration of these systems for future MAb production.
Oils, Microbial Production
Authors: Sakuradani Eiji , Ogawa Jun , Kishino Shigenobu , Ando Akinori , Yokozeki Kenzo , Shimizu Sakayu 
Published: April 2010

AbstractThe term single cell oils is used for unique oils produced by microorganisms. Many attempts have been made to produce useful fatty acids or oils containing them by microbial processes. One example is the production of cocoa‐butter equivalent oil by yeast which abundantly produces stearic acid. The most successful example occurs in the production of oils containing polyunsaturated fatty acids (PUFAs) having more than one double bond. Here, microbial PUFA production is discussed mainly as a typical example of single cell oils. Furthermore, the examples of PUFA transformation by microorganisms to conjugated fatty acids and so on are also introduced.
Organosilicon Compounds, Enzymatic Modification
Authors: Zong Min‐Hua , Tanaka Atsuo , Kawamoto Takuo 
Published: April 2010

AbstractOrganosilicon compounds play important roles in organic chemistry and pharmaceutical applications. Therefore, increasing attention has been focused on the preparation of organosilicon compounds with desired chemical and physical properties by the effective biocatalysts. This article outlines the bioconversion of organosilicon compounds by the use of biocatalysts such as microorganisms, alcohol dehydrogenases, hydrolases, and hydroxynitrile lyases. The preparation of silicon‐containing amino acids and cyanohydrins by the bioconversion is also described. Furthermore, the effects of silicon atom on the enzymatic reaction are discussed with comparative studies by using organosilicon compounds and corresponding carbon compounds as substrates of enzymes.
Osmolarity Effects, Chinese Hamster Ovary Cell Culture
Authors: Min Lee Gyun , Koo Jone 
Published: April 2010

AbstractMedium osmolality is an important factor to consider during recombinant Chinese hamster ovary (rCHO) cell culture. Several studies have shown that hyperosmolality improves the specific foreign protein productivity (q), although the effect of hyperosmolality onqin rCHO cell culture seems to differ between cell lines, clones, and gene dosages. However, hyperosmolality decreases the specific growth rate (μ). The depressed cell growth that occurs at elevated osmolality generates a dilemma in that althoughqis enhanced, a substantial increase in the maximum foreign protein concentration is not attainable. As a remedy to this problem, the addition of osmoprotective compounds, such as glycine betaine, or the regulation of anti‐apoptotic proteins, are offered as potential methods to alleviate the depressed growth and, thus, increase the foreign protein production during hyperosmotic culture.
Phenylalanine Dehydrogenase
Authors: Asano Yasuhisa 
Published: April 2010

AbstractNAD + ‐dependent phenylalanine dehydrogenase (PheDH) was first found to occur in 1984, followed by a number of studies on its enzymological properties, structure, reaction mechanisms, applications to the synthesis ofL‐amino acids from their α‐keto analogs and the microdetermination of Phe and its keto analog.
Photobioreactors
Authors: Tredici Mario R. , Chini Zittelli Graziella , Rodolfi Liliana 
Published: April 2010

AbstractIndustrial production of microalgae is prevalently carried out in raceway ponds. However, there is the diffused perception that open systems have reached their technological limit and that closed photobioreactors (PBR) will prevail in the future even at a very large scale. PBR are flexible systems that can be optimized according to the characteristics of the cultivated species and permit to cultivate microalgae that cannot be grown in open ponds because of contamination. In the last decades PBR have much evolved and plenty of new designs have been proposed. This review focuses on those systems used outdoors at the pilot level and on a commercial scale. The main design criteria for PBR (construction materials, surface‐to‐volume ratio, orientation and inclination, mixing and mass transfer, and temperature control) are outlined, and the principal PBR categories (tubular and flat, horizontal, inclined, vertical and spiral; manifold and serpentine) are illustrated, with examples of commercial plants that have been closed down and are currently in operation. The performance in ponds and PBR is also compared and the issue of productivity evaluation is discussed.
Pichia, Optimization of Protein Expression
Authors: Sreekrishna Koti 
Published: April 2010

AbstractPichia pastorisis a methylotrophic yeast. It is able to use methanol as sole carbon source for energy as well as for growth. It was originally developed by Phillips Petroleum Company (Bartlesville, OK) as an organism of choice for bioconversion of natural gas (methane) into food (single cell protein). With the advent of cloning of its highly regulated alcohol oxidase (AOX1) promoter, availability of auxotrophicPichiastrain [GS115 (his4)], andPichiatransformation protocols, the successful high level expression of several proteins has been readily demonstrated. The purpose of this article is to highlight the strategies that have been used for optimal protein expression with thePichiayeast expression system, which in the past few years has turned out to be a versatile and impressive yeast for the production of proteins.
Plant Cell Culture, Laboratory Techniques
Authors: Fowler Mark Richard 
Published: April 2010

AbstractPlant cell cultures providepowerful experimental tools, for both applied science and fundamental research.Culturing plant cells and tissuein vitromakes some special demands on laboratory facilities, although many large laboratories will have most of the equipment necessary for at least initial experiments with plant tissue cultures. The primary requirement for successful plant tissue culturein vitrois the ability to produce and culture the tissue aseptically. Plant cell cultures tend to grow very slowly and in most cases require a rich culture medium, which means that contamination with a range of microbial organisms can present a real problem.Plant cell cultures also need to be kept in defined, controlled environments. In many respects, this can be achieved through the choice of culture vessel, which for many plant tissue cultures are relatively simple vessels such as petri dishes. These cultures though, will require maintenance in growth rooms that allow control of parameters such as temperature and lighting regime. This requirement may place a considerable burden on laboratories that utilize plant tissue cultures on a large scale, as specialized growth facilities can be expensive. On a smaller scale, many “cabinets” or growth chambers are available that allow plant tissue to be cultured on a small scale at a reasonable price.Once established, plant cell cultures facilitate long‐term growth of uniform plant material and through precise manipulation of the culture environment, permit studies on such diverse topics as plant development, cell division, secondary metabolism, and plant propagation.
Polyhydroxyalkanoates (PHAs): Separation, Purification and Manufacturing Methods
Authors: Chen Guo‐Qiang 
Published: April 2010

AbstractPolyhydroxyalkanoates (PHAs) function to provide bacteria with resistance. PHAs with diverse structures have been developed for various applications including fermentation, materials, packaging, biomedicals, and biofuels. The most critical problem for commercial PHA production is the cost. For many years, recombinant bacteria have been constructed to produce various PHAs with various structures, monomer ratios, and molecular weights for the sake of lowering PHA production costs and improving PHA properties. In the future, we should develop continuous fermentation processes without sterilization, based on simple substrates. In addition, aqueous processes for PHA purification should be developed to further reduce the PHA production costs.
Polysiloxanes, Biocatalytic Functionalization
Authors: Fröhlich Peter , Bertau Martin 
Published: April 2010

AbstractThis article describes methods and reactions for the modification of silicones (polysiloxanes) by chemical and particularly biocatalytic catalysis with reagard to industrial applications. The properties of organosiloxanes are determined by functional groups attached lateral or terminal to the silicone backbone by alkyl spacers. Most well‐established processes by which oligo‐ or polysiloxanes are obtained, use hard reaction conditions, strong acids or bases as catalysts thus resulting in a broad distribution of molecular weight. Biocatalysis by enzymes and whole cells attains increasing relevance as an attractive approach of green chemistry due to physiological conditions of pH, temperature and high stereoselectivity. In a general synthetic route major functionalities represented by amino, hydroxy, vinyl, carboxylate or amide groups are introduced to the alkyl spacered organosiloxane bearing ester, amide, carbamate groups or other functionalities by hydrolysis, amidation and oxidoreductions. In particular for hydrolytic reactions of esters and carbamates grafted onto the backbone, lipases and esterases exhibit high synthetic potential, primarily in non‐conventional media. Hydrolases are available economically on an industrial scale. The biocatalytic functionalizations are generally performed in a two‐phase system of siloxan‐cosolvent and aqueous medium, for which reason the mass transfer of reactants, product and enzyme is limited at the interface. Different feasible methods are depicted to solve the problem by increasing the interface. Microreactors open up new scopes for biocatalytic modifications of organosiloxanes performed by lipase‐catalyzed production of aminosiloxanes. The proof‐of‐concept for biocatalysis in silicone chemistry is highlighted by an ecoefficiency study.
Porous Media, Applications in Biotechnology
Authors: Mota Manuel , Yelshin Alexander , Yelshina Inna 
Published: April 2010

AbstractAfter describing the main characteristics of porous media (porosity, tortuosity, permeability, and diffusivity), the role of porous media in mass transfer is analyzed with the help of numerical examples. Significant differences between the behavior of inert and biological porous media with respect to the response to external factors are considered. Current and prospective applications of porous media in biotechnology and biomedicine are highlighted.
Soluble Protein Expression in Bacteria
Authors: Schein Catherine H. 
Published: April 2010

AbstractThis article summarizes methods for increasing the fraction of recombinant proteins expressed in a soluble form in the cytoplasmic fraction of bacteria. Many recombinant proteins, when expressed at very high levels in bacteria, form insoluble aggregates called inclusion bodies (IBs). Growth conditions can be manipulated to keep protein in a soluble form, including lowering the temperature during induction, choice of host strain and expression vector, or coculturing of proteins that assist in folding. Higher yields can be obtained by mutating the protein or fusing it with various linkers (which can also improve purification by enhancing column chromatography interactions). Eliminating protease or RNase recognition sites can stabilize the protein or mRNA, as can mutations that improve recognition by cofactors that assist in folding.Methodology to simultaneously produce many different recombinant proteins in a soluble form has been developed as part of the structural genomics initiative; these can also be used to for scanning mutagenesis studies. High density bacterial cultivation can be used to produce gram per liter quantities of recombinant proteins at the industrial scale. However, maintaining high levels of soluble protein requires optimizing all aspects of growth, ranging from how the inoculum is stored, to medium details and bacterial harvesting and lysis.
Growth Factors: Protein Processing, Endocytosis, and Intracellular Sorting
Authors: Duex Jason , Sorkin Alexander 
Published: April 2010

AbstractGrowth factor (GF) receptors are extracellular receptors which, when bound by growth factors, initiate intracellular signaling for promoting cellular proliferation, survival, and differentiation. The amount of signaling is generally controlled by both the levels of growth factor and the levels of GF receptors present in the cell, particularly at the cell surface. This review will focus on the mechanisms of endocytosis and postendocytic trafficking that serve to control the levels of GF receptors. The classical experimental system used to investigate these processes is the endocytosis of GF receptors that possess intrinsic tyrosine kinase activity, known as receptor tyrosine kinases (RTKs). We will use the prototypical RTK, epidermal growth factor receptor (EGFR), as the model GF receptor in this discussion since much of the data leading to the current understanding of GF receptor endocytosis was generated using this receptor.Growth factor (GF) receptors are extracellular receptors which, when bound by growth factors, initiate intracellular signaling for promoting cellular proliferation, survival, and differentiation. The amount of signaling is generally controlled by both the levels of growth factor and the levels of GF receptors present in the cell, particularly at the cell surface. This review will focus on the mechanisms of endocytosis and postendocytic trafficking that serve to control the levels of GF receptors. The classical experimental system used to investigate these processes is the endocytosis of GF receptors that possess intrinsic tyrosine kinase activity, known as receptor tyrosine kinases (RTKs). We will use the prototypical RTK, epidermal growth factor receptor (EGFR), as the model GF receptor in this discussion since much of the data leading to the current understanding of GF receptor endocytosis was generated using this receptor.
Protein Ultrafiltration
Authors: Reis Robert Van , Zydney Andrew L. 
Published: April 2010

AbstractProtein ultrafiltration is a pressure‐driven membrane process used for the concentration and/or purification of protein solutions. Ultrafiltration membranes typically have mean pore size between 10 and 500 Å, which is intermediate between reverse osmosis and microfiltration. Although ultrafiltration has often been viewed as a purely size‐based separation, with species larger than the membrane pores being fully retained while smaller species pass freely, separation in ultrafiltration actually occurs because of differences in the rate of filtration of different components across the membrane in response to a given pressure driving force. Solute filtration rates, and thus the membrane selectivity, are determined by both thermodynamic (e.g. partitioning) and hydrodynamic (e.g. transport) interactions. Ultrafiltration is currently used throughout downstream processing for protein concentration, buffer exchange and desalting, protein purification, virus clearance, and clarification. Buffer exchange and desalting are typically accomplished using a diafiltration mode in which the low molecular weight components are washed away from the protein by simultaneously adding fresh buffer (or solvent) to the feed during ultrafiltration. Protein purification is accomplished using high performance tangential flow filtration, with the product collected in either the retentate or filtrate depending on the relative filtration rates. Virus filtration uses larger pore ultrafiltration membranes, which are permeable to protein but provide significant virus removal.
Temperature‐Dependent Molecular Adaptations, Microbial Proteins
Authors: Kumar Sandeep , Singh Satish K. , Gromiha M. Michael 
Published: April 2010

AbstractThis review seeks to present an update on the temperature‐dependent molecular adaptations shown by proteins from psychrophilic, thermophilic, and hyperthermophilic microorganisms. The temperature stress for life on Earth is ancient. Hence, there are multiple routes to psychrophily and thermophily. Electrostatic optimization of protein surfaces, active sites, and subunit interfaces are a frequent route. This natural manipulation of protein stability and solubility via surface electrostatics modulation has many potential applications. Here, we discuss how this principle could be used in a structure‐based biotherapeutic drug design and development.
Reverse Micelles, Enzymes
Authors: Kolisis Fragiskos N. , Stamatis Haralambos 
Published: April 2010

Abstract
Reverse micelles or w/o microemulsions have found wide applications in enzymology, protein chemistry and biocatalysis. Biocatalysis based on reverse micelles, is one of the earliest methodologies where microemulsions were introduced to solubilize enzymes in organic solvents. Reverse micelles have been associated to the idea of a microreactor where the enzyme can be sheltered and protected from solvent detrimental effects providing a unique microenvironment for the enzymes to react with water insoluble or poorly soluble substrates present in the organic phase. The most often investigated enzymes in microemulsions are lipases, because these enzymes are very stable and active in this medium. This review focuses on the fundamental aspects of enzymes encapsulation in reverse micelles, as well as on biotechnological applications based on these systems as reaction media for biotransformations using mainly lipase‐catalyzed processes.
Biosurfactants, Rhaminolipid, Microbial Production
Authors: Walter Vanessa , Syldatk Christoph , Hausmann Rudolf 
Published: April 2010

AbstractRhamnolipids are versatile and environment‐friendly biosurfactants composed of a hydrophilic rhamnose unit and a hydrophobic fatty acid part. This article covers all aspects of rhamnolipid biosurfactants production, from production strains to downstream processing.Features and possible applications of rhamnolipids are illustrated and their biosynthesis is reviewed. Production strains, cultivation strategies, and recovery methods for rhamnolipids are presented from a commercial point of view. Nonpathogenic production strains, which are rarely used for rhamnolipid production, are presented and discussed. Currently rhamnolipids are noncompetitive with established bulk surfactants due to the high production costs. In the final section, the limitations of current rhamnolipid production processes are highlighted and research demands are discussed.
Sampling and Sample Handling for Process Control
Authors: Mattiasson Bo , Hedström Martin 
Published: April 2010

AbstractSampling and sample handling are crucial steps in monitoring and control of bioprocesses. Reproducibility in sampling and handling of the sample are key issues when developing new analytical tools. One of the problems with biotechnological processes is that often, microorganisms or enzymes are present in the sample and their activities have to be stopped in the sampling moment, otherwise the composition of the sample may change before analysis is carried out.Integrated processing of samples can be carried out using flow‐injection analysis with different processing steps such as dialysis, dilution, reagent addition etc.This area is attracting increasing interest now when industrial biotechnology is addressing processes with relatively low margins and where efficient process technology is a prerequisite.