MAKING NATURE WORK FOR YOU: AN INTRODUCTION TO BIOTECHNOLOGY
(August 2004)
Biotechnology is the application of scientific and engineering principles to process biological materials for goods and services. Biotechnology is, therefore, highly multidisciplinary with foundations in many fields including cell and molecular biology, physiology, immunology, microbiology, genetics, biochemistry and chemical and process engineering.
Biotechnologists uses techniques derived from a variety of disciplines (fig. 1). Their main objectives are the innovation, development and optimal operation of processes in which biochemical catalysis plays a fundamental role. Biotechnology relies on each contributing discipline to better understand the technical language, potential and limitations of other areas.
Historically, biotechnology was an art rather than a science, exemplified in the manufacture of products like wine, beer and cheese. Manufacturing techniques were usually discovered by chance but then thoroughly and reproducibly worked out. However the molecular mechanisms were not understood. With major advances in biochemistry and microbiology, these processes have become better understood and improved. Modern biotechnological processes now include a wide range of new products including antibiotics, vaccines and antibodies and a variety of therapeutic proteins. Biotechnology has been further diversified by many new molecular innovations, allowing unprecedented changes to be made to living systems. Transgenic plants and animals are igniting a new era in agriculture and human gene therapy promises to eradicate many diseases which are currently incapacitating and untreatable. Environmentally, biotechnology is allowing major improvements in water and land management as well as bringing solutions to pollution generated by various industries.
A key factor distinguishing a traditional biologist from a biotechnologist is the scale of operation. The biologist usually works in the range of nanograms to milligrams. Biotechnologists, depending on the project, may aim to generate quantities of desired product in kilograms or higher. As such, biotechnology aims to amplify biological processes.
The developments in biotechnology are currently proceeding at a speed similar to that of microelectronics in the 1970s. Although the analogy is tempting, it is probably not realistic to expect that biotechnology will develop commercially at the same spectacular rate experienced by microelectronics. Nonetheless, biotechnology will still have a considerable impact across all industrial uses of the life sciences, in spite of the fact that some traditional means of production are still economically more favourable than the newer biotechnological methods. Chemical means of production that utilize petrochemical based feedstocks are still more economically sound compared to biotechnology driven routes for most industrial chemicals. Biotechnology will undoubtedly have great benefits in the long run in all sectors.
Many new biotechnology companies have spun off from universities. These companies are often technologically driven and multidisciplinary in nature. Product development can involve molecular biologists, clinical researchers, bioprocess engineers and sales staff. The business climate of biotechnology companies is often characterized by rapid change and considerable risk as one biotechnology innovation may quickly supercede another. Another peculiar feature of new biotechnology companies is that their business growth is often highly dependent on venture capital, as they require exceptionally high level of funding before profit sales return.
Biotechnology & Chemical Engineering
Many biotechnological processes may be considered as having a three-component central core, in which one part is concerned with obtaining the best biological catalyst for a specific function or process, the second part creates (by means of technical operation) the best possible environment for the catalyst to perform, and the third part (downstream processing) is concerned with the separation and purification of an essential product or products from a fermentation process.
In the majority of processes so far developed, the most effective, stable and convenient form for the catalyst has been the whole organism. It is for this reason that so much of biotechnology revolves around microbial processes. However, this does not exclude the use of higher organisms, in particular plant and animal cell culture that have played a vital role in the development of therapeutic and diagnostic biological products and will continue to play an increasingly important role in biotechnology.
The second part of the core of biotechnology deals with all aspects of the containment system or bioreactor within which the catalysts must function. Here the combined knowledge of the scientist and the bioprocess engineer interact, providing the design and instrumentation for the maintenance and control of physiochemical environment such as temperature, aeration, pH, etc., thus allowing the optimum expression of the biological properties of the catalyst.
The third aspect of the biotechnology, namely downstream processing, can be a technically difficult and expensive procedure. Downstream processing is primarily concerned with the initial separation of the bioreactor medium into a liquid phase and a solid phase, and subsequent separation, concentration and purification of the product. Chemical engineering principles play a vital role here as well in terms of designing and operation of the separation systems. Downstream processing costs can be as high as 60 – 70% of the selling price of the product as exemplified by the plant Eli Lilly built to produce human insulin. Over 90% of the 200 staff are involved in the recovery processes. Downstream processing represents a major part of the overall cost of most processes but is also the least glamorous aspect of biotechnology. Improvements in downstream processing will benefit the overall efficiency and cost of processes and will make the biotechnology competitive to the conventional chemical processes.
Biotechnology and the Environment
Biotechnology has been successfully employed to reduce or eliminate various forms of air and water pollutants. Methods developed by environmental biotechnologists might use the microorganisms to either break down or sequester pollutants. The concept of using microorganisms to treat pollution problems is not a new idea; microbes were first used as early as 1930s to treat industrial wastewaters. More recently they helped in the cleanup of oil spilled from the Exxon Valdez tanker off the coast of Alaska in 1989 as well as decontaminated water aquifers contaminated with various industrial chemicals such as phenol, trichloroethylene (TCE) and compounds present in various petroleum fractions.
Opportunities for using microorganisms for bioremediation of soils contaminated with various industrial pollutants arose when scientists discovered that there is practically nothing that is not viewed as food by one microbe or another. Just as some insects can feed on leaves that are toxic to others, so some microbes can thrive on molecules that would poison most organisms. Microbes exist in nature that feed on toxic materials such as methylene chloride, detergents, phenol, sulfur and polychlorinated biphenyls (PCBs).
Microbes metabolize the toxic compounds to produce harmless end products such as carbon dioxide, water and salt. The chemical conversions usually involve breaking large molecules into several smaller molecules, much as we break down the complex carbohydrates in our food to simple sugars such as glucose. In some cases, the by-products of a bacterial banquet are not simply harmless but actually useful. Methane, for example, can be derived from a form of bacteria that degrades sulfite liquor, a waste product of paper manufacturing. Methane can then be used in a wide range of industrial applications such as electricity production
Although individual species of bacteria can carry out several different steps of chemical breakdown, most toxic compounds are degraded by group of bacteria living together. Each species in the group work on a particular stage of the degradation process and all of them together are needed for complete detoxification.
Depending on the nature and extent of pollution, microbial clean up can take from a few weeks to a year or more. When the toxic chemicals are gone, the population of bacteria itself dwindles, being replaced by other microbes native to the area and more suited to the new conditions.
(Art by Jane Wang – note that high res versions of image files available here)