Showing papers on "Bioprocess published in 1995"

Bioprocess Engineering Principles

Abstract: This welcome new edition discusses bioprocess engineering from the perspective of biology students. It includes a great deal of new material and has been extensively revised and expanded. These updates strengthen the book and maintain its position as the book of choice for senior undergraduates and graduates seeking to move from biochemistry/microbiology/molecular biology to bioprocess engineering. New to this edition: * All chapters thoroughly revised for current developments, with over 200 pgs of new material, including significant new content in: * Metabolic Engineering * Sustainable Bioprocessing * Membrane Filtration * Turbulence and Impeller Design * Downstream Processing * Oxygen Transfer Systems * Over 150 new problems and worked examples * More than 100 new illustrations

Bioprocessing technology for plant cell suspension cultures

Abstract: Considering various forms of in vitro plant tissue cultures, cell suspension culture is most amenable to large-scale production of natural compounds, owing primarily to its superior culture homogeneity. This fact has already been demonstrated in several largescale applications, including the commercial shikonin process. The scope of this work is to review the state of the art in bioprocessing technologies pertinent to the secondary metabolite production from suspension cultures of callus cells. In the first part of the review, plant cell physiology relevant to bioprocess design is considered. This is followed by an in-depth discussion on the bioreactor design and operation and its effect on plant cell suspension cultures. Finally, recent commercial exploitation and development are summarized. Following the review, related patents and literature are listed.

Principles and Applications of Biosensors for Bioprocess Monitoring and Control

Abstract: Biosensors are useful analytical devices that can be integrated with on-line process monitoring schemes. In this article, the principles and applications of these devices for bioprocess monitoring are considered. Several different types of biosensors are described, and the applications and limitations of flow injection analysis (FIA) for these applications are discussed. It is hoped that the background provided here can be useful to researchers in this area.

Power and limitations of model based bioprocess optimization

Abstract: Since the last few decades the application of system theory concepts and modern model based control techniques to the optimization of biotechnological processes has received a lot of attention. This represents a challenging field of research for the following reasons. First, the dynamics of bioprocesses are determined by the non-linear behavior of living micro-organisms. Therefore, knowledge of reaction kinetics is most often only partial, which represents a serious limitation for mathematical modeling. In addition, bioprocess characteristics are time-varying, which requires on-line adaptation of the model parameters or even the model structure. Second, until now the number of on-line measurement systems is very small, while the measured quantities are most often only indirectly related to the important biological state variables. This inhibits the on-line validation of complex model structures. Therefore, in the past bioprocess optimization used no model at all. However, an adequate mathematical bioprocess description is the basic ingredient for the development of model based control strategies. As a case study, we consider in this paper the optimization of fed-batch fermentation processes involving one limiting substrate for biomass growth and product synthesis, with respect to the volumetric feed rate of this substrate. Three examples illustrate that feed rate profiles which are optimal in the sense of process performance, can contribute at the same time to solving model structure selection and parameter estimation problems as well.

Fuzzy supervisory control of fed-batch baker's yeast process

Abstract: A fuzzy supervisory system for bioprocess control was developed, and applied to baker's yeast fermentation The system was based on hierarchical bioprocess control with fuzzy phase recognition and separate fuzzy control of each process phase A two-level knowledge base included rules both for the phase recognition and control The system was tested by using experimental data of fed-batch baker's yeast cultivations and by process simulations

Bioprocess Development: An Interdisciplinary Challenge

Abstract: Bioprocessing is an essential part of many food, chemical and pharmaceutical industries. Bioprocess operations make use of microbial, animal and plant cells and components of cells such as enzymes to manufacture new products and destroy harmful wastes. Use of microorganisms to transform biological materials for production of fermented foods has its origins in antiquity. Since then, bioprocesses have been developed for an enormous range of commercial products, from relatively cheap materials such as industrial alcohol and organic solvents, to expensive specialty chemicals such as antibiotics, therapeutic proteins and vaccines. Industrially-useful enzymes and living cells such as bakers ‘and brewers’ yeast are also commercial products of bioprocessing.

Challenges in commercial biotechnology. Part I. Product, process, and market discovery.

Abstract: Publisher Summary This chapter describes the challenges in commercial biotechnology. A process is a sequence of operations or steps resulting in the production of a certain product or in a particular treatment or raw materials. A technical field dealing with bioprocessing is called bioprocess engineering or bioprocessing. Most biotechnological processes consist of a chemical reaction process section (fermentation, or bioreaction section) and of a subsequent product recovery section. A process system can be defined by addressing the interrelated and interdependent nature of elements of a process. It can be arbitrarily defined as consisting of the upstream and downstream segments, including those of fermentation, cell recovery, and product recovery processing. Each process system interacts with its environment by means of mass, energy, and information flows. A set of elements and flows determines the internal structure of the process system. Such elements are then described as structural elements. Time and space conglomerates of elements, having a certain common similarity, are called subsystems.

Increase of Productivity in Recombinant Cho-Cells by Enhanced Glucose-Levels

Abstract: Mammalian cells are the preferred production organisms which can produce recombinant proteins in their native, fully glycosylated form. However, the overall cellular productivity is limited, when compared to yeasts and procaryotes. Therefore the main target in bioprocess development for mammalian cell cultures is the enhancement of product yield to achieve economical and competitive product titers. In the outlined presentation we investigated the effects of various compounds on the specific productivity of serum-free growing recombinant CHO cells, with special regard to the effects of the carbohydrate sources. A strictly proportional expressed product formation was observed when compared to the glucose consumption of the corresponding cells. On the other hand, the glutamine metabolism seems to be reduced during enhanced product formation phases. The growth rate was ‘inverse’ regulated depending on the availability of the main carbohydrate (glucose).

Predicting yields for autotrophic and cometabolic processes

Abstract: The goal of bioprocess engineering is to state how the optimum design and control strategy for a bioprocess follow from the metabolism of olism of the particular microorganism. A necessary step toward this goal is to show how the parameters used in quantitative descriptions of a process (e.g., yield and maintenance coefficients) are related to those describing the metabolism [e.g., YATP, (P/O)]. The “yield equation” approach to this problem involves dividing metabolism into the separate pathways for catabolism, anabolism, respiration, and product formation and balancing the production and consumption of reducing equivalents and ATP. The general approach demonstrated previously for heterotrophic cell growth and products of fermentation, is illustrated by three new examples: the cell yield for chemoautotrophic iron-oxidizing bacteria, the cometabolic degradation of chloroform by methanotrophic bacteria, and the theoretical yield of succinic acid from glucose.

11 – Homogeneous Reactions

Abstract: The heart of a typical bioprocess is the reactor or fermenter. Flanked by unit operations which carry outphysical changes for medium preparation and recovery of products, the reactor is where the major chemical and biochemical transformations occur. In many bioprocesses, characteristics of the reaction determine to a large extent the economic feasibility of the project.

Cascades of bioreactors

Abstract: In this thesis a common phenomenon in bioprocess engineering is described : the execution of a certain bioprocess in more than one bioreactor. Chapter 1, a review, classifies bioprocesses by means of a number of characteristics : i) processes with a variable stoichiometry , ii) processes with a constant stoichiometry using biocatalysts , iii) processes with a constant stoichiometry that are autocatalytic . This chapter also offers a method to decide in which cases it can be worthwhile to use more than one bioreactor. The possible advantage is gained by a possible reduction in the total residence time needed to accomplish a certain degree of conversion. The shorter that residence time, the smaller the bioreactor(s) can be, and with that the capital investment reduces. The minimal residence time is attained if the bioreactors all have a different volume. In general the volume of each bioreactor decreases along the series. Moreover, the total volume of the series decreases if an increasing number of bioreactors are used in the series, although that decrease becomes increasingly less. The largest decrease in total residence time occurs by using two bioreactors in series instead of one single bioreactor, whereas the use of more than three bioreactors in series usually offers little advantage since the extra costs for pumps and similar additional parts is getting too high. Chapter 2 describes the optimum design of a series of bioreactors for the case that the biocatalysts are immobilized, and chapter 3 describes this for immobilized autocatalytic systems. In chapter 3 some rather straightforward assumptions are made for the behaviour of immobilized growing cells, which may not be true in reality. Chapters 4 and 5 show the dynamic behaviour of the cells, including an experimental evaluation of such a system. As a model system Nitrobacter agilis cells were used. These cells perform the conversion of nitrite in nitrate, which is of importance for waste-water treatment, more precisely the removal of ammonia. Hereby ammonia is first converted to nitrite, nitrite to nitrate, and nitrate finally is converted to nitrogen gas. The model that is derived in chapter 4 however, has a more general applicability. Chapters 6, 7 and 8 describe a system with a variable stoichiometry. In a first bioreactor insect cells are produced, which are infected with a baculovirus in one or two subsequent bioreactors. The infected cells then will produce polyhedra, which have a use as bioinsecticide. According to the current knowledge, insects cannot develop resistency against baculoviruses. Moreover, baculoviruses are extremely specific for an insect species, which means that useful insects are not affected. In these chapters it is shown that the production in continuously operated series of bioreactors is not unlimited in time, and that that is caused by the so-called passage effect : if the viruses have infected a cell a number of times, their infectivity decreases and the reaction stops. The model described in chapter 7 can predict what should be the optimal reactor configuration, and in chapter 8 this is experimentally shown : the cells must be grown in a bioreactor with a feed of medium, and if that bioreactor is filled part of its contents are pumped to a second bioreactor in which infection with baculovirus occurs. During the time that the bioreactor in which the cells are grown is filled, the infected cells in the infection bioreactors produce polyhedra. After that the infection bioreactor is largely emptied, so that some virus remains in the reactor, and new cells are added, after which the infection proceeds, and so on. In this manner the time that the production process runs can prolongate fourfold as compared to a fully continuous process. The number of applications of series of bioreactors is limited. An important cause for this is that, in practice, the for most bioprocesses required sterility is not easily maintained if the process is executed in more than one bioreactor. Chapter 9 shows a possible solution to that problem : in the presented Multiple Air-Lift Loopreactor up to three air-lift loopreactors in series are incorporated into one bioreactor. List of explained words. Air-Lift Loopreactor : A bioreactor without stirrer that consists of two compartments : a riser and a downcomer. Mixing and oxygen transfer are accomplished by sparging air at the bottom of the riser. Autocatalytic :A reaction where the biocatalyst itself is produced. Baculovirus :A rod-shaped virus occuring in insects. Biocatalysts : Compounds, usually enzymes, that accelerate a reaction but do not take part in the reaction. Bioprocess Engineering : The application-oriented science of the integration of one or more biological disciplines and process engineering. Chapter 7 is a good example of the integration of virology and process engineering. Immobilized : In this thesis this means the inclusion of cells in a carrier, to retain them in a bioreactor. Insect cells : Cells of an insect (in this case Spodoptera frugiperda ), capable of growth in suspension. Polyhedra : The form of baculoviruses occurring in nature. To protect the virions against environmental influences they are packed in protein matrices, the polyhedra. Once arrived in the gastro-intestinental tract, the polyhedra are dissolved and the virus particles are released, after which the insect is infected. Stoichiometry : The ratio, on a molar basis, between the substrate offered and the product formed. Residence time : The average time spent in a bioreactor.

Biosensor and chemical sensor technology : process monitoring and control : developed from two symposia sponsored by the Division of Biochemical Technology and the Biochemical Secretariat at the 209th National Meetings of the American Chemical Society, Anaheim, California, April 2-6, 1995

Abstract: Biomolecular Sensing for Bioprocess and Environmental Monitoring Applications Use of an Acoustic Wave Device as a Liquid Chromatography Detector Immunosensors for Detection of Chemical Mixtures: Antibody Affinities, Selectivities, and Cloning Adaptation of a Fiber-Optic Biosensor for Use in Environmental Monitoring A New Method for the Detection and Measurement of Polyaromatic Carcinogens and Related Compounds by DNA Intercalation Chemically Modified Electrode for Hydrogen Peroxide Measurement by Reduction at Low Potential Enzyme Sensors for Subnanomolar Concentrations Electroenzymatic Sensing of Fructose Using Fructose Dehydrogenase Immobilized in a Self-Assembled Monolayer on Gold Recent Advances in Bioprocess Monitoring and Control Optical Measurement of Bioprocess and Clinical Analytes Using Lifetime-Based Phased Fluorimetry Biosensor for On-Line Monitoring of Penicillin During Its Production by Fermentation Selective Measurement of Glutamine and Asparagine in Aqueous Media by Near-Infrared Spectroscopy An Expert System for the Supervision of a Multichannel Flow Injection Analysis System Hybrid Process Modeling for Advanced Process State Estimation, Prediction, and Control Exemplified in a Production-Scale Mammalian Cell Culture Optimization of an Escherichia coli Fed-Batch Fermentation Using a Turbidity Measurement System The Automation of Two Flow-Injection Immunoassays Using a Flexible Software System

Modelling of L-lysine fed-batch culture based on combined neural network estimators

Abstract: Modelling of a bioprocess was developed by combining three neural network estimators (NNEs). The bioprocess was for fed-batch culture of L-lysine production. The NNEs were NNE1, NNE2, and NNE3. NNE1 was applied to estimate the consumed sugar concentration, L-lysine concentration, and cell optical density. NNE2 was utilized to determine the off-gas concentration of O2 and CO2 while NNE3 was employed to predict the agitation speed. These NNEs possessed their own distinct functions and could be used independently. Combination of the NNEs based on neural network gave an easy and significant way for modelling a bioprocess.

From new drug discovery to bioprocess operations

Abstract: There is a wide variety of areas in in biotechnology where engineering skills need to be applied. The goal of biotechnology based companies is to develop both a new product and its manufacturing process as fast as possible. It is in the area of enhancing the rate of new product development where engineering skills are critical. The author outlines a few examples and then focuses in detail on the application of expert system technology to bioprocess operations. Due to the use of color slides which are not easily reproduced, this document does not cover the entire talk that was presented at the 13th Annual International Conference IEEE Engineering in Medicine and Biology Society. >