Chemical Engineering and Its Role in Biochemical and Biomedical Engineering

The historical and conceptual roots of chemical engineering from the late 19th century are in the applications of the knowledge of chemical systems, particularly reacting systems, in industrial processes.  Throughout the 20th century chemical engineering has deepened its scientific foundation through incorporation of advances in the fundamental physical and chemical sciences.  This broadening scientific base of chemical engineering has led to an expansion in the applications of chemical engineering to many new industries, including microelectronics, advanced materials, and environmental pollution treatment. 

More recently, incorporation of the principles of the biological and life sciences, particularly molecular and cellular biology, has provided chemical engineers the opportunity to contribute to biotechnology and related industries and to the medical field through both biochemical engineering and biomedical engineering.  The emphasis of chemical engineering education on the molecular basis of materials and biomaterials provides chemical engineers with the skills necessary to tackle problems from the very small scale in cells and biological tissues to the very large scale in industry and the environment.     

Chemical engineering as a profession was established over 100 years when it arose from the combination of mechanical engineering and chemistry1.  In the developing chemical industry in the late 19th century there was a critical need for engineers involved in the design, construction, and operation of chemical factories to have a solid understanding of both engineering and chemical principles, particularly chemical reaction stoichiometry and kinetics.  The first degrees in chemical engineering in the USA were awarded at that time and the American Institute of Chemical Engineers was established in 1908. 

Throughout the 20th century, the profession of chemical engineering developed as the chemical and petrochemical industries2, 3 expanded and as more universities developed formalized chemical engineering curricula that incorporated solid fundamental education in the physical and chemical sciences.  As the educational component of chemical engineering developed to include deep fundamental analysis of physical and physical chemical processes, particularly after the 2nd World War with the study of mass, momentum, and energy transport4, 5, the role of chemical engineers in industry and society broaden considerably6.

Because of the emphasis on fundamental principles in the education as opposed to the equipment-specific emphasis of the earlier years, chemical engineering employment diversified into new fields such as microelectronics processing and environmental engineering and pollution control7.  The solid fundamental training of chemical engineers in the analysis of complex multiphase systems with chemical reactions and molecular transport was recognized in many industries and government laboratories.  Today, the education of modern chemical engineers includes the full range of fundamental subjects in chemistry, physics, and engineering sciences such as thermodynamics, mechanics, fluid mechanics, heat and mass transport, and chemical reactor design.  Understanding of these subjects, coupled with the capability to utilize advanced computational methods to solve systems of partial differential equations that describe how materials behave under a very large range of conditions, provide the modern chemical engineer the ability and skills to tackle many problems to improve our modern way of life.

Development of the science of biology, particularly the chemical-based science of molecular biology was the hallmark of human scientific achievement during the late 20th century.  Humans have, of course, long used products from the natural world for medicine, food, clothing, and shelter.  However, the fundamental scientific principles of biology and biochemistry had not been clearly understood well enough to permit a rational approach to developing new materials and processes that could be used and adapted for improving human life.  A number of processes and products, including fermentation for making alcohol and various foods, the use of enzymes for tanning leather, the use of bacteria for biological waste treatment and the production of antibiotics from mold culture, have been used and developed in the past8.  These developments have arisen due to a large amount of trial and error that has been necessary for selecting the proper microorganisms and the proper biomolecules for a given task.  It has only been over the last thirty years that our knowledge of the principles of molecular and cellular biology and the development of techniques for manipulating cells, organelles, and biological macromolecules has advanced to a level that removes some of the trial and error involved in developing new processes and products.

The field of bioengineering encompasses the applications of the life sciences for the betterment of humankind.  Generally, bioengineering has been segmented into biochemical engineering and biomedical engineering.  Biochemical engineering arose from the combination of the life sciences with chemical engineering for the industrial production of a wide range of materials, including pharmaceuticals such as insulin and organic compounds such as ethanol, from cells by industrial scale fermentation.  These processes typically used bacteria to make useful materials in large factories and in particular the biotechnology industry where such materials are made has been based upon key scientific advances9 including the following.

a) Recombinant DNA - This allows the insertion of genes from one organism into another to cause the second organism to produce a protein that was only made by the first.  Examples include the production of human insulin by bacteria.  In addition, our overall understanding of molecular genetics is leading to the ability to manipulate the metabolism of cells to create pathways for the breakdown of toxic waste materials or to make complex non-protein products.

b) Site directed mutagenesis - The alteration of a single amino acid (i.e. one monomer) in a large protein.  This allows us to tailor-make enzymes and proteins that will be best suited for a particular task.  For example, alteration of particular amino acid sequences of protein degrading enzymes has provided increased thermal stability and thereby permitted their use in detergents.

c) Monoclonal antibodies and the increased understanding of the immune system - Antibody molecules are widely used in separation processes since they can be made to have a very high selectivity (molecular recognition) for a desired species.  They are also currently being developed for use as catalysts (catalytic antibodies).

Chemical engineers can apply their traditional strengths in transport phenomena, thermodynamics, process control, kinetics, and reactor design to problems in using and developing biotechnological products and processes.  Single celled organisms such as e. coli (intestinal bacteria of humans) have been considered as chemical reactors with a large number of chemical reactions occurring simultaneously in series and parallel.  Chemical engineers are actively developing models of the complex regulatory pathways involved in the cell for controlling all of these reactions in order to develop ways to make new products and processes such as the hot area of biofuels.  Furthermore, some researchers like to consider a cell as a miniature chemical plant with reaction, separation, and control processes occurring throughout.  In addition, transport limitations are very important for nutrients to enter the cell and for products to leave the cell. Transport across cell membranes and walls, across external boundary layers, and diffusional limitations inside the cell can control the rate of production of valuable materials.  All of these phenomena can be directly analyzed using the fundamentals taught in undergraduate and graduate chemical engineering courses.

The use of cells and biological macromolecules as industrial processing tools is rapidly advancing with such applications as waste treatment and organic molecule synthesis.  For example, many industrial and textile dyes are currently made with organic reactions, however the processing requires large amounts of toxic solvents and generates a large amount of waste.  Current research has found ways to produce certain dyes in microorganisms.  With feed stocks consisting of ordinary nutrients such as glucose and various salts and with easily biodegradable waste products this production method is much more environmentally acceptable than the current processes.  In addition to the use of cells as processing tools, biomolecules are also used in industry.  The largest use of an immobilized enzyme, biocatalyst, is for the production of high fructose corn syrup, the major ingredient in most soda. 

Biomedical engineering is specifically concerned with engineering applications to improve human health10 and it has broad roots in electrical and mechanical engineering where some of the first applications of engineering involved electrical instrumentation, e.g. pace makers, and prosthetic devices, e.g. artificial limbs.  During the last few decades of the 20th century, chemical engineers started to become more involved directly in biomedical engineering through several key areas.  Chemical engineers had long been involved in the development, analysis, and application of many types of synthetic polymeric materials11.  As medicine and medical treatment technologies developed there became a clear and strong need for advanced materials that could be used inside or with the human body.  Chemical engineering developed polymeric materials for delivery of medicines to particular places in the body and for use in other medical procedures12.  During that that time, the science of cell biology, particularly mammalian and human cell biology, was advancing and chemical engineers started to work in the development of human cell based medical therapies.  The ability to grow mammalian and human cells outside of the human body is a key aspect of the new field of tissue engineering13, 14 where engineers are striving to make replacement body parts from the cellular components.  Chemical reaction engineering is critical for the design, development, and operation of bioreactors to grow human cells and to make such tissues.  The ability to analyze the combination of diffusion with chemical reactions and hydrodynamic flow in such systems provides the chemical engineering the skill necessary to advance this field.

In summary, an education in chemical engineering with the traditional knowledge of the chemical and physical sciences and with further knowledge of the biochemical and biological sciences will provide students with the foundation to approach and solve many of the important problems confronting humans.  Problems from human health to energy and the environment must be addressed by engineers with such background.  To reach their full potential, to attain such a high degree of knowledge, and to acquire advanced skills in applying that knowledge, it is highly recommended that chemical engineers pursue graduate education. 
           

by: Bruce R. Locke
Professor and Department Chair
Department of Chemical and Biomedical Engineering
Florida State University
FAMU-FSU College of Engineering

REFERENCES

1. Furter, W.F., ed. History of Chemical Engineering. Advances in Chemistry Series, ed. M.J. Comstock. Vol. 190. 1980, American Chemical Society: Washinton, DC.
2. Spitz, P.H., Petrochemicals, The Rise of an Industry. 1988, New York: John Wiley & Sons.

Landau, R. and N. Rosenberg, America's High Tech Triumph. Invention and Technology, 1990. Fall: p. 58-63.
4.  Bird, R.B., W.E. Stewart, and E.N. Lightfoot, Transport Phenomena. 1960, New York: John Wiley and Sons. 780.
5.  Bird, R.B., W.E. Stewart, and E.N. Lightfoot, Transport Phenomena. 2nd ed. 2002, New York: John Wiley & Sons.
6.  Scriven, L.E., The Role of Past, Current, and Future Technologies in Chemical Engineering. Chemical Engineering Education, 1987. December: p. 65-69.
7.  Amundson, N.R., ed. Frontiers in Chemical Engineering, Research Needs and Opportunities. 1988, National Academy Press: Washington, DC.
8.  Aharonowitz, Y. and G. Cohen, The Microbiological Production of Pharmaceuticals. Scientific American, 1981. 245: p. 141-152.
9.  Watson, J.D., et al., Molecular Biology of the Gene. 5 ed. 2003: Benjamin Cummings.
10. Montaigne, F., Medicine by Design. 2006, Baltimore: The Johns Hopkins University Press.
11. Peppas, N.A. and R. Langer, New Challenges in Biomaterials. Science, 1994. 263: p. 1715-1720.
12. Langer, R., New Methods of Drug Delivery. Science, 1990. 249: p. 1527-1533.
13. Saltzman, W.M., Tissue Engineering. 2004, Oxford: Oxford University Press.
14. Lanza, R.P., R. Langer, and W.L. Chick, Principles of Tissue Engineering. 2 ed. 2000, Austin: Academic Press, R.G. Landes Company.

 

Science / Engineering courses / colleges