Bioprocess Engineering Principles

Pauline M. Doran

• Publisher: Academic Press
• Year: 1995
• ISBN:
  9780080528120
• Topic: Ciencias biológicas
• Subtopic: Biotecnología

The emergence and refinement of techniques in molecular biology has changed our perceptions of medicine, agriculture and environmental management. Scientific breakthroughs in gene expression, protein engineering and cell fusion are being translated by a strengthening biotechnology industry into revolutionary new products and services. Many a student has been enticed by the promise of biotechnology and the excitement of being near the cutting edge of scientific advancement. However, graduates trained in molecular biology and cell manipulation soon realise that these techniques are only part of the picture. Reaping the full benefits of biotechnology requires manufacturing capability involving the large-scale processing of biological material. Increasingly, biotechnologists are being employed by companies to work in co-operation with chemical engineers to achieve pragmatic commercial goals. For many years aspects of biochemistry and molecular genetics have been included in chemical engineering curricula, yet there has been little attempt until recently to teach aspects of engineering applicable to process design to biotechnologists.
This textbook is the first to present the principles of bioprocess engineering in a way that is accessible to biological scientists. Other texts on bioprocess engineering currently available assume that the reader already has engineering training. On the other hand, chemical engineering textbooks do not consider examples from bioprocessing, and are written almost exclusively with the petroleum and chemical industries in mind. This publication explains process analysis from an engineering point of view, but refers exclusively to the treatment of biological systems. Over 170 problems and worked examples encompass a wide range of applications, including recombinant cells, plant and animal cell cultures, immobilised catalysts as well as traditional fermentation systems.*
* First book to present the principles of bioprocess engineering in a way that is accessible to biological scientists
* Explains process analysis from an engineering point of view, but uses worked examples relating to biological systems
* Comprehensive, single-authored
* 170 problems and worked examples encompass a wide range of applications, involving recombinant plant and animal cell cultures, immobilized catalysts, and traditional fermentation systems
* 13 chapters, organized according to engineering sub-disciplines, are groupled in four sections - Introduction, Material and Energy Balances, Physical Processes, and Reactions and Reactors
* Each chapter includes a set of problems and exercises for the student, key references, and a list of suggestions for further reading
* Includes useful appendices, detailing conversion factors, physical and chemical property data, steam tables, mathematical rules, and a list of symbols used
* Suitable for course adoption - follows closely curricula used on most bioprocessing and process biotechnology courses at senior undergraduate and graduate levels.

PART 1

Introduction

1

Bioprocess Development: An Interdisciplinary Challenge

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.

Table 1.1 gives examples of bioprocesses employing whole cells. Typical organisms used and the approximate market size for the products are also listed. The table is by no means exhaustive; not included are processes for wastewater treatment, bioremediation, microbial mineral recovery and manufacture of traditional foods and beverages such as yoghurt, bread, vinegar, soy sauce, beer and wine. Industrial processes employing enzymes are also not listed in Table 1.1; these include brewing, baking, confectionery manufacture, fruit-juice clarification and antibiotic transformation. Large quantities of enzymes are used commercially to convert starch into fermentable sugars which serve as starting materials for other bioprocesses.

Table 1.1

Major products of biological processing

Our ability to harness the capabilities of cells and enzymes has been closely related to advancements in microbiology, biochemistry and cell physiology. Knowledge in these areas is expanding rapidly; tools of modern biotechnology such as recombinant DNA, gene probes, cell fusion and tissue culture offer new opportunities to develop novel products or improve bioprocessing methods. Visions of sophisticated medicines, cultured human tissues and organs, biochips for new-age computers, environmentally-compatible pesticides and powerful pollution-degrading microbes herald a revolution in the role of biology in industry.

Although new products and processes can be conceived and partially developed in the laboratory, bringing modern biotechnology to industrial fruition requires engineering skills and know-how. Biological systems can be complex and difficult to control; nevertheless, they obey the laws of chemistry and physics and are therefore amenable to engineering analysis. Substantial engineering input is essential in many aspects of bioprocessing, including design and operation of bioreactors, sterilisers and product-recovery equipment, development of systems for process automation and control, and efficient and safe layout of fermentation factories. The subject of this book, bioprocess engineering, is the study of engineering principles applied to processes involving cell or enzyme catalysts.

1.1 Steps in Bioprocess Development: A Typical New Product From Recombinant DNA

The interdisciplinary nature of bioprocessing is evident if we look at the stages of development required for a complete industrial process. As an example, consider manufacture of a new recombinant-DNA-derived product such as insulin, growth hormone or interferon. As shown in Figure 1.1, several steps are required to convert the idea of the product into commercial reality; these stages involve different types of scientific expertise.

Figure 1.1 Steps in development of a complete bioprocess for commercial manufacture of a new recombinant-DNA-derived product.

The first stages of bioprocess development (Steps 1–11) are concerned with genetic manipulation of the host organism; in this case, a gene from animal DNA is cloned into Escherichia coli. Genetic engineering is done in laboratories on a small scale by scientists trained in molecular biology and biochemistry. Tools of the trade include Petri dishes, micropipettes, microcentrifuges, nano- or microgram quantities of restriction enzymes, and electrophoresis gels for DNA and protein fractionation. In terms of bioprocess development, parameters of major importance are stability of the constructed strains and level of expression of the de...