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close this bookEco-restructuring: Implications for sustainable development (UNU, 1998, 417 pages)
close this folderPart I: Restructuring resource use
close this folder3. Ecological process engineering: The potential of bio-processing
View the document(introductory text...)
View the documentEditor's note
View the documentIntroduction
View the documentThe current situation: The status of biotechnologies
View the documentPotential and promises
View the documentMarket penetration by biotechnology
View the documentBarriers to penetration
View the documentFinal remarks
View the documentNotes
View the documentReferences

(introductory text...)

Anton Moser

Editor's note

The best introduction to this chapter is a book written over 20 years ago by Lewis Thomas (1974). Thomas, writing about medicine, makes the important point that current medical technologies are either "non-technologies" or "halfway technologies" (1974, p. 32). In the medical case, Thomas defines "non-technologies" as supportive therapy, or "caring for" a person with a disease whose underlying causes and mechanisms are not really understood. As examples, he mentions cancer, rheumatoid arthritis, multiple sclerosis, stroke, and advanced cirrhosis. Today one would certainly add AIDS and Alzheimer's disease to that list. Although most of the diseases on his list are now better understood than when Thomas wrote, it is doubtful that any of them, except some types of cancer, have moved even to the next (half-way) level.

It is fairly natural to suggest that other technologies can be characterized along the same axis as medical technologies. A non-technology in the production sphere is perhaps one in which nature does essentially all the work. The current technologies of forestry, ranching, and dairy farming (for instance) are virtually non-technologies. Nature does everything. The human contribution is largely limited to culling and harvesting (with a bit of tree planting, animal breeding, and veterinary medicine).

"Half-way technologies" are the ones that dominate current practice. In the medical sphere, Thomas defines them as "the kinds of things that must be done after the fact, in efforts to compensate for the incapacitating effects of certain diseases that one is unable to do very much about" (1974, p. 33). His examples include organ transplants, most types of surgery, wheelchairs, and the "iron lung" that was used to assist victims of infantile paralysis to breathe. Technologies that assist detection and diagnosis (but not cure) are also surely in this category.

Conventional agriculture may be characterized as a half-way technology. In the case of agriculture, the state of conventional technology can be summarized as breeding, tilling, fertilizing, seeding, weeding, and harvesting. Machines utilizing fossil fuels have been developed to do a lot of the tilling, seeding, weeding, and harvesting, while chemicals (also based largely on fossil fuels) do the fertilizing and pest control. Yet this combination is wasteful, harmful to wildlife and soil, and unsustainable in the long run. This would seem to be "half-way" technology. Moser argues that knowledge based biotechnologies can potentially do a lot more, reducing the need for machines and chemicals on the one hand, and reducing harmful side-effects on the other.

The third type of medical technology, according to Thomas, is "the kind that is so effective that it attracts the least public notice; it has come to be taken for granted." Vaccines, antibiotics, and hormone treatments of endocrine disorders are examples. The ability to clone and grow replacement organs in vitro would be a big step forward over the current techniques, but the ability to regrow organs in vivo would, of course, be the ultimate substitute for surgical transplants. The discovery of the Salk vaccine, which essentially made "iron lungs" obsolete and eliminated infantile paralysis as a threat (and forced the "March of Dimes" to find another target for fund-raising), perfectly exemplifies the transition from "half-way" technology to truly advanced technology. An important and perceptive observation by Thomas is that what we often think of as "high-tech" medicine is, more often than not, actually the expensive and complicated "half-way" variety rather than the truly effective variety.

Indeed, most other conventional production technologies are undoubtedly very primitive when compared with the technologies utilized by nature. Is there any fundamental reason why complex metal, ceramic, or plastic structures could not be "grown" as an organism grows? In the very long run, I see no fundamental barrier. In fact, current developments in semi-conductor manufacturing and advanced ceramics technology seem to point in that direction.

Moser's principal contribution, in this chapter, is to lay out some of the next intermediate steps in this possible evolutionary development. His notion of "eco-technology" corresponds to a considerably more advanced stage of this possible evolution, but one that can be plausibly envisioned in general terms at least by a technological optimist - within the next half-century.

I have to say, here, that Moser's original paper contained a great deal of interesting material, including a considerable discussion of measures of and criteria for eco-sustainability. Because much of this seemed to be beyond the scope of his assignment, or was essentially covered in chapter 1, the editors were forced to prune it rather drastically for lack of space. It is to be hoped that, as a biologist, Professor Moser will recall that roses, too, must be pruned to make them bloom more abundantly. I have also added some parenthetical remarks in a few places in Professor Moser's text.

Introduction

Technologies cannot be assessed in isolation. Sustainable technologies must satisfy a number of requirements and constraints. These include (i) the limited capacity of the biosphere to absorb wastes and recover from injury, both globally and on a regional level, (ii) the limits of cultural and social acceptance, (iii) economic feasibility, and (iv) technical feasibility. In addition, it is obvious that technological "fixes" alone will not suffice to assure long-term sustainability, although technology plays an essential role. The main aim of this paper is to evaluate the potential of bio-processing and to clarify its likely contribution to long-term sustainability.

The current situation: The status of biotechnologies

Four main fields of technical application (apart from food and beverages) are well known. These are health care, agriculture, environmental remediation, and industrial materials processing. These are discussed briefly in the following pages.

Health care (pharmacology and medicine)

The health-care field of biotechnology includes the production of vaccines, hormones (such as insulin), therapeutics, diagnostics, and antibiotics via conventional process routes, such as cell cultures, using natural organisms. Antibiotics are normally made in this way. For instance, penicillin, the first antibiotic, is produced by a fungus. Increasingly, however, "modern" pathways are being exploited, based on genetically engineered organisms (GEOs). These GEOs either lack certain genes or contain genes from other organism.1 As a result they have properties not found in the natural versions of those organisms.

Editor's note: Most of the early applications of genetic engineering technology have been in this field, owing to the high value of some pharmaceutical products.2 For example, Eli Lilly began producing human insulin by recombinant DNA techniques in 1982. Interferon, human and animal growth hormones, and monoclonal antibodies are examples of early applications. Public attention is usually drawn to the advertised benefits of these innovations for society, especially the possibility of sharply cutting the costs of important categories of drugs. Most of these short-term benefits have been consistently overestimated, and the length of time needed to take a new drug or diagnostic technique through the tedious and complex approval process is consistently underestimated. Nevertheless, by the late 1980s several biotechnology firms - especially Amgen - had developed successful and profitable products and a number of others had been sold to international pharmaceutical giants.

Agriculture and food technology

Older agriculture shaped natural plants and animals to human uses by means of breeding techniques. The modern branch of agriculture uses chemicals derived from biological materials (such as hormones and plant growth regulators, single cell protein, vaccines), microbial cultures, and new plants and animals created deliberately by genetic engineering modifications of existing organisms by recombinant DNA methods. Potential and obviously desirable future applications of genetic engineering are to introduce nitrogen fixation capability and/or disease resistance into important crops, such as potatoes, corn, or rice.

Public debate reflects serious safety concerns here, too.

Environmental biotechnology

Environmental biotechnology is understood in a broad sense as the application of biotechnologies - mainly micro-organisms - to the solution of existing environmental problems, including the treatment of sewage, waste water, and even soil decontamination. Early applications include biogas systems. Genetically engineered organisms are also increasingly used in this field, resulting in the same public concerns about safety mentioned above.

Industrial biotechnology

Industrial biotechnology is an established field, including cheese-making, winemaking, the brewing of beer, and the production of baker's yeast, vinegar, alcohol, acetone, acetic acid, citric acid, etc. from carbohydrates and sugars, mainly by fermentation. GEOs are not yet being applied in this area, although it would seem to be an inevitable evolutionary development.

It is quite important for the evaluation of biotechnologies to consider the normal life cycle of technologies. The different stages of development are marked by the production of molecules of increasing complexity (e.g. bulk chemicals, single cell protein, drugs).

A rather visionary, more distant future stage can be denoted "eco-technology," or simply "eco-tech." The name is intended to convey the idea that biotechnology eventually begins to substitute for more conventional technologies in a wide range of applications, resulting in significant environmental benefits and a much closer approach to long-term sustainability.

Scientifically the advantages of bio-processing over chemical processing can generally be characterized as follows:

- big-catalysts are highly active, specific, and selective; their regeneration is easier than in the case of chemical catalysts; there are no environmental problems as with heavy metals;

- reaction conditions are mild (temperature, pressure, and also concentrations);

- internal energy is supplied by energy-enriched compounds, e.g. ATP, which are formed during metabolism;

- impure, diluted, and inactive raw materials can be used, owing to the high specificity and selectivity of big-catalysts;

- big-products are biodegradable in natural cycles.

The competitiveness of biotechnologies in comparison with chemical technologies is discussed later in this chapter. The most competitive opportunities for biotechnology, at present, lie in the domain of high-price/low volume "specialty" products. However, increasing success in this domain, together with rising prices for petroleum and other fossil hydrocarbons, suggests that opportunities will gradually increase over coming decades in the domain of low-price/high-volume "commodity" products.

Two observations apply to biotechnologies in general. In the first place, to produce highly complex and specific products such as pharmaceuticals, or to degrade toxic substances in the environment, the biological path is already clearly superior to the chemical path in many cases. A similar competitive break-point can be expected in the near future in several other cases, where bio-processing becomes yearly more competitive. To be more specific, the most successful current applications of big-processes are as follows:

- the production of foods (e.g. cheese, yogurt, soya sauce) and beverages (wine, beer);

- the production of complex molecules on the industrial scale for use in health care for humans, animals, and plants (pharmaceuticals and therapeutics, antibiotics, proteins, steroids, etc.);

- the degradation/purification of wastes and toxic substances in the environment (sewage, industrial wastes, water treatment, etc.);

- sequential reactions in one-step processes (e.g. the production of steroids), highly selective stereo-specific conversions, etc.

There are other domains where the advantages of "biologicals" compared with "chemicals" are likely to be established soon. These include the reclamation of soil, the recycling or sequestration of carbon dioxide, the production of biofuels from waste agricultural or forest biomass, the creation of new and more productive plants capable of surviving in different climates, resisting diseases, etc. The beneficial products of bio-processing will surely increase in the next decade.

A second observation is that process economics for biotechnological products (thus far) suffer generally from the fact that they depend on growth cultures. The latter involve lower concentrations, higher water content, and, consequently, higher energy requirements for separation and purification than does chemical processing, in general. The need for more sophisticated equipment, and more highly educated technicians, also contributes to the current competitive disadvantage of biotechnologies as compared with chemical processing.

Thus, despite their potential benefits in terms of long-term sustainability, most big-processes are not yet economically competitive. Biotechnology is not expected to become competitive on a wide range of fronts before the year 2030 (OECD 1989). Even this forecast will prove overoptimistic unless efforts toward commercialization are accelerated, especially by strengthening process engineering sciences (Moser 1994). Research programmes in big process engineering have been recently stepped up in Japan (1992), the United States (1992), and Europe (1993).

In the following section, the status of the various biotechnologies is considered in more detail.

Potential and promises

The near-term opportunities for bio-processing can be summarized briefly as follows:

- the production of organic chemicals with the aid of big-catalysts, e.g. enzyme technology (fine chemicals, starch and cellulose, bio-polymers), fermentation products (ethanol, single cell protein, antibiotics, nitrogen fixation for fertilizers), and animal and plant cell cultures;

- the use of biomass for fuel and energy production;

- food production and processing;

- the production of industrial materials (e.g. vegetable oils, pulp, and paper) from biomass.

A few examples will help to put the situation in perspective.

Bio-catalysts (enzymes)

Enzymic conversions, as a consequence of the potential advantages mentioned, are in an excellent position to contribute to a cleaner environment. The use of enzymes offers industry an opportunity to replace processes using aggressive chemicals with mild big-processes exhibiting minimal impact on the environment. The raw materials come from agriculture. Also the effluents are non-toxic, although they contain nitrogen, phosphorus, and organic matter. This leads to high amounts of wastes in the water. The major part of the spent dry matter is collected as a sludge and then spread on nearby farmland. The sludge consists of dead biomass, filter aid, nutrient surplus, and an insoluble residue.

In 1990, Novo Nordisk, a Danish pharmaceutical manufacturer, reused 500,000 m3 of sludge containing 5 per cent dry solids including 800 metric tons of nitrogen and 285 metric tons of phosphorus. The sludge instead acts as an efficient slow-releasing N-P fertilizer: more than 90 per cent of N is bound in organic matter, which means that the evaporation of ammonia is minimal. Figure 3.1 depicts the situation of this enzyme production plant, which fits nicely into an ecological cycle with agriculture (Falch 1991; Novo Nordisk 1993). The full-scale process, now in operation, is shown in the diagram.

Biological control agents (big-pesticides)

A big-pesticide is a living organism or a product derived from microorganisms or plant sources that kills the pest in order to sustain its own growth cycle. The characteristics of a big-pesticide are pest specificity, environmental stability, safety, and low cost. Bio-control agents, despite being new entrants in the field, have already made substantial contributions in preserving the fertility of the soil, maintaining an ecological balance, and preventing resurgence of pests. This has been achieved with little harm to non-target animals and plants and with few side-effects. The potential of big-toxins being active as insecticides, herbicides, and fungicides is basically known. However, widespread practical application is still in the wings, mainly owing to high costs.


Fig. 3.1 Closed-cycle technology in the Novo Nordisk enzyme production plant (Source: Falk 1991)

A good example of application is in India, where the big-pesticide market is around 100,000 tons per year, representing 3 per cent of the total market. Biologicals have a market share of 0.5 per cent of global chemical pesticides, as of 1995, while in the year 2000 a penetration rate of about 10 per cent is expected by some experts, out of a total global pesticide market of US$40-45 billion. At the moment the biotoxins produced from Bacillus thuringiensis (Bt) dominate, with nearly 70 per cent of the market.

Bio-pesticides can already substitute effectively for some chemical pesticides in agriculture (e.g. protection of cotton, sugar cane, oil seeds such as groundout, rapeseed) as well as floriculture and horticulture. They have uses too in public health (e.g. control of disease vectors of malaria, filariasis, and encephalitis with B. sphaericus and B. thuringiensis formulations). Bio-pesticides can be broadly classified into the following categories, indicating a broad diversity in species as well as in specific actions:

- predators pathogens

- parasites/parasitoids

- pheromones

- kairomones

- neem oil

Predators

Commonly used predacious species are Cryplolaemus nontrouzuri, Chrysopa, Scymnus, Coccivera, and Nephus spp. against mealy bugs and Cerilocorus nigritus and Pharoscymnus houri against scale insects. Ladybird beetles are used to protect rice (against brown plant hopper), fruits such as citrus and grapes, and plantation crops such as coffee.

Pathogens (viral, fungal, bacterial)

Among the different entomopathogens, referred to as "biorational pesticides" as viral pathogens, the most important are the bacillo viruses. More than 10 types of such viruses have been isolated and extensively studied for their potential in pest management. Of these, nuclear polyhedrosis viruses (NPV) and granulosis virus (GV) are found to have good potential for pest control. The use of fungi to control pathogens that incite plant disease is another concept that has been in existence for some time. Insects infected with fungus exhibit general lethargy, slow growth, cessation of feeding, and changes in colour. The difference between fungi and other pathogens is that fungi do not have to be consumed by the insect to cause disease; instead they grow through the insect's skin. Many fungi are found to be pathogenic to a number of pests such as Metarhizium anisopilae, Beauveria brongniartii, Anopheles stephensi, and Trichoderma.

The most prominent bacteria in biological control are in the genus Bacillus, the group of Gram positive, rod-shaped bacterium. Bacillus thuringiensis (Bt) is the most widely known and researched aerobic spore-forming bacterium within this group for insecticides properties and is differentiated from other spore-forming bacilli by the presence of a parasporal body that is formed within the sporangium during sporogenesis. The parasporal body is a high molecular mass protein crystal that is referred to as crystalline protein delta-endotoxin. The insecticidal activity of B. thuringiensis products is based on the deltaendotoxin. Bacillus thuringiensis is primarily a pathogen of lepidopterous pests. Being a natural protein, Bt endotoxin is highly biodegradable. It is also degradable by ultraviolet radiation. As a result, it is environmentally safe, because it cannot leave behind any residues to contaminate the soil, water, or food. Naturally occurring Bt are spore forming bacteria. The spores are resistant to desiccation, high temperature, UV, and biodegradation.

Parasites/parasitoids

The families Mermithidae, Steinernematidae, Romanomernis culicivoran, Goniazas nephantidis, Bracon brevicormis, Sturmiopsis inferens, and Trichogramma are of special importance as examples of insect parasitic forms.

Pheromones

Insects rely on a sense of smell and communicate with each other by releasing specific chemicals (odours) to indicate their selection of food plants, sites to lay eggs, location of prey, defence and offense, mate attraction, and courtship. These specific chemicals that deliver intra-specific communications between individuals of single species are called pheromones. Between 600 and 1,000 pheromones have been isolated, identified, and synthesized, many for insects.

Kairomones

Kairomones are compounds emitted by an insect to convey a behavioral response to a member of a different species. They carry an advantage to the receiver (e.g. compounds used by parasites to locate a host). They are utilized in conjunction with Trichogramma to improve their efficiency in parasitization.

Neem oil

Extracts of Neem seed provide various crops with resistance to insect pests. Neem oil contains several chemicals of which the most potent one, "Azadirachtin," interacts with the reproductive and digestive processes of insects. Neem oil acts in a number of subtle ways, especially as a repellent and anti-feedant. It also has a growth regulatory effect by disturbing the insect's metabolism during various phases of development.

Another interesting field of research is allelopathy, where the metabolic substances produced by one plant inhibit the growth of another plant. This can be regarded as a potential alternative to the use of chemical herbicides and the evolution of herbicide-resistant crops. Plants also offer quite innovative chances for new applications in the area of removal of heavy metals from the environment, e.g. "phytoremediation" (Salt et al. 1995), especially from soil, e.g. "phytoextraction" (Kumar et al. 1995), and from aqueous media, e.g. "rhizofiltration" (Dushenkov et al. 1995).

Bio-leaching of ores

Bio-leaching utilizes sulphur-loving bacteria that live in the ore itself. Examples include Thiabacillus ferroxidans, Thiobacillus thiooxidans, and Leptospirillum ferroxidans. When exposed to oxygen and carbon dioxide they obtain metabolic energy by reacting oxygen with sulphur, producing sulphuric acid as a metabolic waste. Compared with conventional heap leaching methods (using sulphuric acid recovered from ore roasting), big-leaching can offer real economic advantages. Typically the economic feasibility differs for several plants on several site-specific factors such as concentrations, leaching rates, and residence times. Bio-leaching is commercially applied for the recovery of copper and uranium in the United States and for gold in South Africa and Brazil. The main obstacle is the investment in conventional plants (TME1992).

The Biox® Genmin process for gold leaching involves the oxidation of a sulphitic concentrate slurry in a series of stirred tanks. Large volumes of compressed air are sparged into the tanks to fulfil the oxygen and carbon dioxide demand of the bacteria. A retention time of 3-5 days results in more than 90 per cent conversion of gold. The oxidized slurry then flows into a series of counter-current decantation thickeners to separate solids from acidic solutions. After neutralization to a pH of 11, cyanide is added and the gold is dissolved. Bio-oxidation currently offers real economic advantages over roasting and pressure oxidation for production plants with a capacity of less than 1,200 tons per day.

Denitrification of drinking water

In the denitrification of drinking water, denitrifying bacteria reduce nitrates and nitrites to harmless nitrogen gas and oxygen, which they use for metabolic purposes. A full-scale denitrifying plant is in operation in Austria, using a 2 m3 fixed-bed big-reactor system, operating with a natural population of microbes as denitrifiers. Because it is based on a naturally existing strain of bacteria, which accumulates during the start-up phase itself, sterile process operation is unnecessary. The process economics of denitrification are shown quantitatively in Table 3.1, which compares biological and physico-chemical approaches (Moser 1996).

Table 3.1 Process costs for the denitrification of drinking water, comparing biological and chemical paths


Costs (US$/m3)


Investment

Running

Total

Biological + ethanol

0.15-0.27

0.10-0.15

0.26-0.47

Heterotrophic de-NO3


Biological

Physical




p

0.024

0.011





0.048

0.023




m

0.022

0.020





0.034

0.030





0.057

0.046




c

0.067

0.067




w

0.003

0.124




a

0.001

0.002


Physical-chemical electrodialysis

0.21-0.38

0.20-0.26

0.39-0.52

Source: Moser (1996).
a: analyses; c: chemicals; m: maintenance; p: personal; w: waste removal.

Biopolymers

Nowadays a large number of synthetic polymers are produced from petroleum derivatives because they are cheap, are available, can be prepared and processed easily, and are subject to few fluctuations of quality. Moreover, synthetic polymers offer a wider range of characteristics than natural polymers. However, genetic engineering offers at least the possibility of producing natural polymers with equivalent properties without the need for large-scale chemical processing.

There are two different ways to obtain polymeric materials from plants that are useful for engineering purposes:

1. making use of the original polymeric structure of the plant material by conserving most of it and chemically modifying only side chains;

2. degrading the plant material chemically, or having it degraded by animals or micro-organisms, and subsequently synthesizing new polymers by means of chemistry or biotechnology.

Quite a few classes of plant polymers can be used as engineering materials without degrading the polymer backbone. Cellulose is one.

The biosphere is abundant in cellulose, from timber, cotton, flax, and hemp. (Cellulose is the basis of rayon, cellophane, and celluloid.) Other natural polymers include natural rubber (a cis-polyisoprene), gutta-percha, lignin, polyphenols, and gums. Technologically useful polymers derived from animals also include proteins, such as wool, silk, leather, horn, gelatin, casein, chitin, and chitosan.

Some polymers with possible industrial application are produced by microorganisms. Biopolymers (e.g. polysaccharides), with properties and applications similar to those of plant gums, are secreted by certain bacteria and can be obtained by means of biotechnology. In the 1980s processes were developed to produce polyhydroxy-alkanoates (PHAs) as thermoplastics on an industrial scale. PHAs are polyesters that are produced by a great variety of micro-organisms as a cellular storage material. The most widespread type of PHA is PHB (polyhydroxybutyrate). However, its properties are not quite suitable to serve as a thermoplastic. This is why methods to produce similar substances with improved processing and application properties are sought.

As a result of these efforts a copolymer of polyhydroxybutyrate and polyhydroxyvalerate (PHB/V) has been developed, with properties very much like polypropylene. This biopolymer, called "biopol," is produced by ICI in Great Britain by a fermentation process using glucose and propionic acid as organic substrates. The latter is currently derived from mineral oil but there are also ways to produce it from renewable raw materials by biotechnological methods. Biopol is biodegradable and therefore can be used for packaging products for quick disposal. In Germany a shampoo bottle made of biopol is on the market. This may be only the beginning (Moser 1994; Braunegg and Lefebvre 1993).

Use of genetic engineering

"Modern biotechnology" consists of new techniques, based on recombinant DNA technology, monoclonal antibodies, hybridoma techniques, cell fusion, vector-initiated gene techniques, and novel methods of cell and tissue cultures, resulting in genetically engineered organisms (GEOs).

The complexity, as well as the costs of development, increase in the following sequence (Swaminathan 1992): biological nitrogen fixation, plant tissue culture, embryo transfer, monoclonal antibody production, plant protoplasm fusion, rDNA for disease diagnosis, biocontrol agents, animal vaccine development, rhizobia improvement, plants, animals. Regardless of the high costs, there is no debate over the question of whether or not developing countries should begin genetic species engineering. Even the poorest should be thinking about a "survival kit" based in modern techniques; for example, a country with root crops as a staple food should initiate a tissue culture laboratory to facilitate the importation of tissue cultures of virus-free clones developed abroad. This would also allow rapid propagation if the plants proved adaptable to local conditions and acceptable to local producers and consumers. Table 3.2 gives some examples of genetic engineering activities and their actual and potential benefits.

It is generally agreed that the potential use of genetic techniques is very promising. Their application can further promote sustainability by, e.g., diversification of agricultural, forest, and fishery production systems, supplementation of genetic resources, and development of life forms appropriate to formerly impossible agricultural situations. A major consequence is considered to be the reduction of economic risk, but environmental risk is also likely to be reduced.

Current technologies can modify a single gene or chromosome. Major future breakthroughs will require more complex transfers. For example, at least six gene modifications would be involved in transferring nitrogen-fixing ability to cereals. Longer-term progress thus depends on further advances in basic science, notably in such areas as genome mapping. Bio-engineering applications are still extremely limited. The potentials have barely begun to be exploited. They are currently being held in check by the need for still more research to identify more useful genes plus more research to avoid harmful effects and big-safety hazard.

To decide whether an activity is pro- or contra-nature, I have suggested a series of four eco-principles (Moser 1996):

1. non-invasiveness

2. embeddedness

3. sufficiency

4. efficiency

Table 3.3 applies principle (1) to various types of biotechnology.

Indigenous technologies: Food and health care

Ancient knowledge is a source of inspiration for sustainable technology development. Meso-American cultures had wide technological activities resulting from the combination of cultural, biological, and ecological diversities (Lopez-Mungia et al. 1994). A famous example in agriculture comes from the Incas, who were able to grow cereals at an altitude of 4,000 m with extraordinarily high productivity (10 tons/ha), although modern techniques (with chemical fertilizers) yield only 4 tons/ha. This 3,000year-old "waru-waru" process is completely natural, having a renaissance in Bolivia under the name of "socca collos." The plants are grown on platforms 1 m in height, 4-10 m wide and 10-100 m long, made from soil dug from the canals. Water absorbs the sun's heat by day and radiates it back by night, protecting the crops against frost by creating a layer at +4°C. By capillary effects water ascends to the roots of the plants. Sediments from nitrogen-rich algae and plant and animal remains serve as fertilizer.

Table 3.2 GEO success stories

Agronomic trait

Breakthrough

Crop

Potential benefit

Insect resistance

Immunity from boll- worm, caterpillars, corn borers, hornworms...

Cotton

Reduced pesticide costs, reduced crop losses (c. US$1.5 billion), increased yields

Disease resistance

Protection against tobacco mosaic virus, rice tungro virus, cucumber mosaic virus...

Tomato, rice, cucumber

Increased yield (25% for tomatoes)

Herbicide resistance

Tolerance for non- selective roundup herbicides

Sugar beet, maize, cotton, tobacco, potato

Less labour-intensive weeding needed

N-fixation

Stimulation of nodule- like structures in roots

Rice, wheat

Reduction in fertilizer costs

Drought resistance

Genes inserted from species growing in deserts, e.g. cacti

Wheat, corn, soybean et al.

~40% less water needed

Baking

Gene modification

Baker's yeast


Cold-tolerating microbes

Deletion of gene for ice-nucleation protein

Potato, straw- berry

~30% profit increase

Crop-ripening qualities

Antisense gene to block enzyme formation involved in softening/ ripening

Tomato

Increased solid content and longer shelf-life

Disease- attacking microbes

Seedling roots soaked in a solution of modified bacteria

Stone fruits, nuts, roses

Losses reduced at minor cost (~US$1/litre)

Insecticidal microbes

Modified Bacillus thuringiensis

Various

Replacement of chemical insecticides, reduced costs

Table 3.3 Clarification big-processes and biotechnologies by degree of invasiveness

Non or low invasive (wisdom or common-sense based)

Use of those natural strains of micro-organisms, plants, and animals widely available in classical biotechs for food and feed and waste treatment

Use of simple selection and mutation (natural screening methods)

Use of GEOs where proved to fulfil all eco-requirements/eco-principles Use of enzymes in fully biocompatible, aqueous systems

Medium invasive; based on classical natural and agro-sciences such as microbiology, biochemistry, cell biology, and engineering

Use of species cultivated in "modern biotech" laboratories (e.g. within the pharmaceutical industry and in plant and animal breeding) using modern mutation and selection methods (scientific screening)

Use of enzymes in non-biocompatible, non-aqueous media

Highly invasive; based on molecular biology and genetic engineering

Use of genetically modified organisms with modifications on the gene/genome level

Use of transgenic species; gene transfers on the level of "high biotech" (monoclonal antibodies, biocide-resistances) using, e.g., hybridoma techniques, cell fusion, vector-initiated gene technology

When Europeans arrived, the Incas had domesticated between 60 and 80 edible plants after centuries of interaction with ecosystems and species. In addition, more than 600 non-cultivated plants with adequate nutritional value, 300 species of fish, and 101 species of insects were used as food. Although much of this knowledge has evidently been lost, some of it may be recoverable. Surely the effort would be worth while. Meanwhile, the simple fact that such knowledge did exist at one time constitutes a powerful argument for preserving biodiversity.

Indigenous technologies are also very rich sources for human health care (big-drugs). Some international firms have initiated joint ventures with tropical countries to identify active compounds from roots and plants (Girardet 1987). Table 3.4 lists some examples of products from indigenous processes.

Table 3.4 Products stemming from indigenous technologies

Basic techniques in agriculture

Waru-waru: sophisticated nature-integrated agriculture in the Andes

Chinapas: the "floating gardens" in the lakes, i.e. artificial isles

Others described in "Codices Florentino"

Medicinal plants

Echinacea purpurea ("red sun heat"): antiseptic, antibiotic, antiviral

Sepherdia rotundifolia ("buffaloberry"): ointment against eye infections

Artemisia tridenta ("big sagebrush"): against rheumatism and colds

Ayahuasca

Balche

Borrachero

Guatillo

Ololiuqui

Chicha

Teonancatl

Ayurvedic medicine (India)

Colourings

Cochinilla (coccus cacti L.), red pigment

Indigo from "xiuhquilitl" (indigofera sufruticosa), blue

(recombinant E. cold based industry in Mexico)

Orange ink from achiyotl (bixa oreyana)

Red ink from haematoxylum brasiletto

Xantophyles from flowers of cempazuchitl (tagetes erecta)

Chilli (annus capsicum)

Bio-fertilizers

The growing need for fertilizers to enable a relatively fixed amount of arable land to support a growing human population is clear. Are chemical or biological fertilizers the best choice? A strong argument for replacing water-soluble chemical fertilizers such as urea, used in quantities up to 250 kg/ha, is that as much as about half of it goes directly into the groundwater and much of the remainder is lost to denitrifying bacteria. Bio-fertilizers such as Rhizobium can be applied in lesser amounts - as little as 0.5 kg/ha potentially resulting in reduced costs.

For example, one can imagine an interrelated system combining a big fertilization plant (Rhizobium) with a sugarcane plantation and ethanol production where the main mass fluxes are consumed internally within the three operations. Further products could be added (food and feed, biological control agents such as Bacillus thuringiensis, bio-polymers for packaging materials, industrial raw materials, etc.), as shown schematically in figure 3.2 (Moser 1996).


Fig. 3.2 Example of a technology mix utilizing agriculture-integrated bio-processing

It is known that in tropical countries there are a great number of plants that are able to live in symbiosis with nitrogen-fixing bacteria such as Rhizabium species (for leguminous plants) or associated symbiotics, e.g. Azosperillum for sugar cane. Genetic manipulation is possible, in the case of Rhizobium species, for further improvement. Some plants depend symbiotically on other microbes for nitrogen fixation. Recently it has been found that such microbes live not only in the roots but sometimes also on the surface of the plant (Doebereiner 1994). There are also non-symbiotic N-fixing bacteria (e.g. azobacter, cyanobacteria, blue and green algae). Research in this area is still at the earliest stages and the very fact that much of value remains to be learned constitutes a strong argument for preserving biodiversity.


Fig. 3.3 Hemp (cannabis saliva) as a typical renewable material for a diversity of applications

Plant-matter-derived products

There is a renaissance of plant-derived bulk raw materials in the United States (Robbelen et al. 1991). In the past decade, technological advances have lowered the cost of producing high-quality products from plant matter, while environmental regulations have raised the cost of using petroleum-derived products. Another potential source of renewable materials is the large amount of waste organic material from agriculture and forestry, especially paper pulping, municipal solid wastes, and food processing. The total is nearly 350 million metric tons/year in the United States alone.

The potential of using plants as industrial raw materials, instead of crude oil, has been neglected up to now owing to the low cost of petroleum. Consequently petrochemicals are the primary source of several categories of industrial materials. In effect, oil has replaced plant-derived matter not only for most textiles but also for significant uses of glass, metals, wood, and even paper. As one example of the potential for increasing the use of plant matter, the case of hemp is illustrated in figure 3.3. Practically all products can, in principle, be produced from plant materials. The basic technologies exist; only cost considerations, and sometimes quality differences, are preventing introduction to the market. The full potential of plant materials for replacing petrochemicals is shown schematically in figure 3.4.


Fig. 3.4 Production paths from renewable raw materials to industrial products

Agro-based "industrial ecosystems"

An example of a possible interconnected but self-contained network of different activities to exploit plant-derived materials was shown in figure 3.2. There are other interesting possibilities for arranging a series of interconnected conversions, where each step uses the waste stream from the step before, with the final result that very little biomass is wasted.3 A second example (Paul) 1994) is the case of beer brewing, shown in figure 3.5, where the liquid waste stream is used as nutrient for fish farming for the production of proteins. An indirect advantage is that the production of 1 kg protein via fish needs only 30 per cent of the feed (in caloric terms) needed to obtain red meat from animals.


Fig. 3.5 "Zero emissions research initiative" applied in the beer brewing industry (Source: Pauli 1994)

Another good example of an integrated big-process is the use of "green juice" from grass and potatoes for the production of dried grass pellets and co-products such as lactic acid, amino acids, other fermentation products, biogas, and inorganic fertilizers (Kiel 1992). A further example of combining many kinds of specialized workshops or factories into a unified ecological complex is that of Aoxue Companie in Anyang/Henan province in China (Wang 1995). This began in 1988 as a simple cornstarch factory. This factory has been innovative in finding uses for wastes. Most of the original wastes are now utilized through "food-chain" adding successive processes to produce higher valued by-products. The range now includes flour, corn syrup, inositol, corn oil, corn wine, protein forage, and protein powder. Other interesting cases from "eco-villages" have been compiled (Swaminathan 1994, table 7).

Table 3.5 presents a pattern of different activities characteristic of some "eco-villages" in India and China.

Table 3.5 Main eco-technologies in China's "eco-villages"

Biogas digester using wastes

High-efficiency production in agriculture

Edible mushroom production using crop and animal by-products

Earthworm raising

Fly pupae production

Chicken waste used as swine feed

Rice-field fishery

Multi-layer fish culture

Raising of natural enemies of pests

Biological control of erosion

Windbreak building

Firewood production

Agro-forestry techniques

Biological wastewater treatment

Intercropping

Solar heater

Market penetration by biotechnology

The processing of plant matter into final industrial products or consumer products is potentially much less environmentally burdensome than the processing of fossil fuels. The latter requires additional chemicals, resulting in a serious disposal problem. In particular, the pyrolysis process applied to plant materials generates no harmful wastes.

A decade age, virtually the only plant-matter-derived products on the market were adhesives and lubricating oils and a handful of intermediate chemicals. Today, plant-derived products compete in just about every major product category. They enter the market by displacing some petroleum-derived product in a portion of its market, and then gradually increase their market share. This is outlined in more detail in table 3.6. Fourteen product categories represent over 90 million of the 108 million metric ton (m.t.) commodity petrochemical market. In all cases, the prices of competitive big-products have dropped since 1985; for example, in the case of inks this drop was over 30 per cent.

Admittedly, most plant-derived consumer products are not yet competitive with their petrochemical counterparts. But the price premium for plant-derived products has dramatically diminished. Even when their costs are higher, plant-based products are gaining market share as a result of a combination of "green" consumerism and government regulation. A number of plant-based products have established their reliability and quality, not to mention environmental value. The cost of big-products should continue to drop and their market share should continue to expand. As table 3.6 reveals, the amount of these eco-products was projected to increase by over 5 million tons by 1996. This would almost double the amount of plant matter used for industrial purposes from the 1990 level. Detergents and plastics account for one-third of the projected market expansion.

Table 3.6 Near-term potential in the United States for plant-matter-based industrial products

Industrial product

Current production (million m.t. per year)

Derived from plants (%)

Cost (US$/kg)

Reduction in cost of plant based products (%)

Projected increase in plant-based products by 1996 ('000 m.t.)



1992

1996

Oil derived

Plant derived

Since 1985

By 1996


Wall paints

7.8

3.5

9.0

0.50

1.20

14

10

429

Special paints

2.4

2.0

4.5

0.80

1.70

3

5

60

Pigments

15.0

6.0

9.0

2.00

5.80

20

15

465

Dyes

4.5

6.0

15.0

12.00

21.00

25

20

405

Inks

3.5

7.0

16.0

2.00

2.50

30

10

315

Detergents

12.6

11.0

18.0

1.10

1.70

-

10

882

Surfactants

3.5

35.0

50.0

0.50

0.50

20

5

525

Adhesives

5.0

40.0

48.0

1.60

1.40

15

2

400

Plastics

30.0

1.8

4.3

0.50

2.00

-

50

750

Plasticizers

0.8

15.0

32.0

1.50

2.50

20

20

136

Acetic acid

2.3

17.5

28.0

0.33

0.35

5

2

241

Furfural

0.3

17.0

21.0

0.75

0.78

10

2

12

Fatty acids

2.5

40.0

55.0

0.46

0.33

5

5

375

Carbon black

1.5

12.0

19.0

0.50

0.45

10

25

105

Data sources: Chemical Marketing Reporter, Chemical & Engineering News; US Industrial Outlook, US Department of Commerce.

For example, inks based on soya oil first entered the US market in 1987. By 1991, 50 per cent of the 9,100 magazines and 75 per cent of daily newspapers were printed with soy-based ink. Aside from price, the key obstacle to the introduction of inks based on vegetable oils has been their slow drying time, which poses fewer problems in newspaper printing but more in magazine printing. This fact constitutes a significant technical challenge.

The interplay of public regulation, consumer sophistication, and private entrepreneurship has brought "biologicals" produced from renewable raw material into almost every major product category. Much larger markets can be achieved through concerted marketing and commercialization. Spurred by the surplus of agricultural crops, governments and some trade associations have targeted new market developments, focusing on those new markets as alternative crops that impact directly on the consumption of fossil fuels. Currently, the best return to biomass is available by displacing petroleum from high value specialty chemical markets. These markets tend to be very small except for half a dozen chemicals. About 90 per cent of all petroleum products are presently used as fuels, the fuel market is the most interesting long-term prospect.

Active research continues to develop processes for the conversion of lignocellulose to ethanol. Although potential margins in this area appear to be greater than in starch-based ethanol conversion, they are realized only if markets can be found for carbon by-products such as lignin or furfural. Unfortunately, given the disparity between fuel requirements and chemical markets, these by-products would saturate existing chemical markets even at relatively modest levels of ethanol production.

More than 20 oilseed crops are grown in the United States, with soybean dominating. About 1 million tons of vegetable oil are used as feedstock's for industrial products such as plastics, surfactants, adhesives, and lubricants, with prices varying from 32 cents per kg for sunflower oil to almost US$10/kg for jojoba oil. Table 3.7 summarizes the situation of oil-crop raw materials for fuels and industrial products manufactured in the United States (USOTA 1992; Robbelen et al. 1991).

Table 3.7 Yields and prices of potential and conventional oil-crop raw materials used for fuel and industrial production in the United States

Material

Crop yield (m.t./ha)

Oil yield (m.t./ha)

Oil price (US$/kg)

Important product categories

Bladderpod

10.0

3.9

-

Plastics, fatty acids, surfactants

Buffalo gourd

14.0

5.1

-

Epoxy fatty acids, resins, paints, adhesives

Castor

4.4

2.3

0.80

Dyes, paints, varnishes, cosmetics, polymer resins, big-pesticides

Coconut

11.0

8.0

0.46

Polymer resins, cosmetics, soap, pharmaceuticals, plasticizers, lubricants

Corn

34.0

7.0

0.62

Ethanol, fermentations, resins

Crambe

7.5

3.0

1.55

Paints, industrial nylons, lubricants, plastic, foam suppressors, adhesives

Cuphae

10.0

4.0

-

Surfactants, lubricants, glycerine, biochemicals

Euphorbia

9.0

4.5

-

Surfactants, lubricants, paints, cosmetics

Honesty (money plant)

10.0

4.0

1.53

Plastics, foam suppressors, lubricants, cosmetics, industrial nylon

Jojoba

15.0

8.3

9.60

Cosmetics, pharmaceuticals, inks, plastics, adhesives, varnishes

Lesquerella

7.5

1.8

-

Paints, lubricants, hydraulic fluids, cosmetics

Linseed

5.2

2.1

0.50

Drying oils, paints, varnishes, inks, polymer resins, plasticizers

Meadowfoam (limnathes)

11.2

3.2

-

Cosmetics, liquid wax, lubricants, rubber, higher fatty acids (C20-C22)

Palm oil

-

12.5

0.34

Fermentation products, soap, wax, tin plating, fuel processing, polymers

Rapeseed

10.0

4.0

1.30

Plastics, foam suppressors, lubricants, cosmetics, adhesives

Safflower

7.0

2.8

0.80

Paints, varnishes, fatty acids, adhesives

Soybean

9.5

1.9

0.40

Inks, paint solvents, plasticizers, resins, pharmaceuticals, adhesives

Stokes aster

9.0

3.9

-

Plastic resins, plasticizers, paints

Sunflower

5.8

4.3

0.32

Plastic resins, plasticizers, fuel additives, surfactants, agro-chemicals

Vermonia

7.5

1.7

1.60

Plastics, alkyd paints, epoxy fatty acids

Data sources: USOTA (1992); Robbelen (1992).

Stricter environmental regulations may provide attractive alternatives for stimulating the biomass industry by targeting environmentally friendly products. The costs involved can sometimes be internalized in the producer's economics. But, more often, they entail external social costs, which allows government to make the cost benefit analysis and provide incentive programmes.

In summary, chemicals from biomass, whether from new or from existing crops, face two major obstacles. The first is that high production entails competing for large-volume, low-margin markets. These markets tend to be volatile, as are the traditional feed/food commodities markets. The second obstacle is that high-margin products tend to have low-volume markets. Commodity chemicals have large markets and are usually low in costs, selling for US$1-3/kg. Specialty chemicals tend to have smaller markets (e.g. about US$56 billion in the United States) and command prices over US$4/kg.

Despite these obstacles, biomass-based commodities could eventually displace many petroleum-based products in the fuel and chemical markets, even without major price increases for petroleum. Obviously, the rate of market penetration would be increased if (or when) petroleum prices rise. The production of biomass-based commodities could potentially reduce dependency on non-renewable resources. Diversification into such areas also opens up new opportunities for the agro-forestry sector, at least where overproduction has been a problem in the past (as in Europe).

Barriers to penetration

To implement and accelerate these changes, a number of conditions must be met. Most of the points made in this section have already been made, but need emphasis. For one thing, it is vitally important to preserve biodiversity, not just for its own sake, but to preserve the genetic information embodied in living organisms. It is not just a question of finding whole organisms with valuable properties. It may be equally important to find organisms with just one valuable property that can be traced to a particular gene or group of genes. It is this possibility that raises hopes of giving food crops the ability to fix nitrogen, or to resist insects, or to tolerate saltier water or colder or hotter temperatures, or to metabolize and break down chlorinated aromatics, such as PCBs, and so on.

It is also important to focus more research on bio-processing. The potential for substituting organic enzymes for inorganic catalysts is worthy of far more attention than it has ever received. The same is true of the use of microorganisms for processing low-grade metal ores or purifying industrial wastes containing heavy metals.

Of course, it is important to develop and to use genetically engineered organisms (GEOs) in a sustainable way. This will require extensive and coordinated research in other sciences, including social and cultural factors. A series of open questions must be asked and answered concerning any application of GEOs.

There are scientific arguments for questioning the scientific validity of the basic premises of genetic engineering. A major assumption is that each specific feature of an organism is encoded in one or a few specific, stable genes so that transferring a gene results in the transfer of a discrete feature, and nothing else. This, however, represents an extreme form of genetic reductionism. It fails to take into account the complex interactions between genes and their cellular, extra-cellular, and external environments. Changing a gene's environment can produce a cascade of further unpredictable changes that could conceivably be harmful.

In the case of genetic transfer to an unrelated host it is literally impossible to predict the consequences: the stabilizing "buffering" control circuits for a gene are exposed to disruption and may be ineffective in new hosts. Owing to the high degree of complexity of any living organism, firm predictions of outcomes are nearly impossible because genomes are known to be "fluid." In other words, they are subject to a host of destabilizing processes such that the transferred gene may mutate, transpose, or recombine within the genome. It can even be transferred to a third organism or another species. In short, the evolutionary stability of organism and ecosystem may be disrupted and threatened. Like the genie in the bottle (in the tale of Aladdin's lamp), once a GEO is deliberately released, or inadvertently escapes from containment, it can never be recalled, even if adverse effects occur. GEOs may migrate, mutate, and multiply.

In addition, there are serious ethical issues concerning the patenting and ownership of life-forms, including implications for cultural values and for indigenous peoples and poor countries.

Editor's note: It is impractical to summarize these issues here, but it is clear that there are many legitimate concerns. Scientists and the business world tend to take the view that the general public should be excluded from the inner circles of decision-making, on grounds of inadequate technical knowledge. But this attitude is essentially undemocratic. It is also likely to backfire. It is worthwhile recalling that nuclear power technology has been discredited largely as a result of public distrust of what the so-called "experts" in government and industry were telling them. To overcome the public knowledge gap, some countries are organizing lay conferences (e.g. NEM 1996).

As an exemplary case, Norway's Gene Technology Act, section 10 (Norway 1993), includes four criteria for a GEO to be acceptable:

- safe to people

- safe to the environment, i.e. the entire ecosphere

- beneficial to the community

- contributing to sustainable development.

Of course, these criteria are quite general. There are endless arguments over how these criteria should be tested and measured. More specific criteria to qualify a micro-organism as "environmentally safe" have been put forward. For instance (Lelieveld et al. 1993):

- non-pathogenic for plants and animals

- unable to reproduce in the open environment (including by delayed reproduction of survival forms such as spores)

- unable to alter equilibria irreversibly between environmental microbial populations

- unable, in the open environment, to transfer genetic traits that would be noxious in other species.

Editor's note: The overriding concern will be safety. It is all too easy to envision GEOs escaping into the natural environment and causing irreversible changes in natural ecosystems. The damage that can be caused by species being introduced inadvertently into environments where they have no natural enemies are well known. A few reminders will help make the point. The rabbit, no problem in Europe, became a major pest when it was introduced into Australia. The sea lamprey, introduced into the Great Lakes via the Welland Canal, has caused great harm to the freshwater fishery there. Dutch elm disease, imported to North America from Europe, has virtually wiped out the most beautiful shade trees of the eastern part of the continent. Another disease of unknown origin has totally wiped out the American chestnut trees, which once dominated the eastern forests. The Japanese beetle also caused enormous damage to agriculture before it was brought under control by pesticides. If such damage can be caused by species that already exist, some sceptics will (and do) argue that the problem could be worse with deliberate genetic manipulation in the picture.

But even the foregoing criteria are ambiguous in a number of ways, because it is unclear how it is to be determined whether or not the criteria are satisfied. It is likely that, in practice, the process of testing and certification for GEOs will be no less rigorous (and possibly much more so) than the current process for drug testing in the United States. Moser takes the view that deliberate ecosystem modification (whether or not GEOs are involved) is wrong and should be prohibited on the grounds of being contra natural (owing to "invasiveness". In principle it is easy to agree, but in practice it seems unlikely that Moser's view will prevail.

Apart from safety and environmental security, there are a number of other questions to be asked and answered with respect to any proposed application. These include questions concerning costs, benefits, and secondary impacts (e.g. reduced need for extractable raw materials, reduced CO2 emissions, remediation of polluted rivers, lakes, or soil, and the maintenance of biodiversity). But, again, it is impossible to go further into detail here.

Final remarks

To summarize, a number of conclusions can be set forth. In the first place, it is safe to say that biotechnologies can and doubtless will contribute significantly to long-run sustainability. They can contribute to solving existing problems such as food security, especially in the developing world (China, India). There is still significant potential for improving the yield and productivity of crops (e.g. rice) and animals, as well as improving nutritional value and taste, disease and pest resistance, storage life, and tolerance of heat, cold, saltiness, wetness, and aridity. A great and likely innovation of the coming decades will be the development of nitrogen-fixing staple crops, such as corn, wheat, and rice. Enormous strides can be expected in aquaculture, fishery management, and food processing, not to mention drinking water purification, composting of garbage, sewage treatment, biomass-based energy production, soil fertility, and decontamination. Developments such as "boneless" breeds (e.g. of trout), "seedless" fruits, and "antifreeze" genes (e.g. for salmon, tomatoes) will also make life interesting.

"Eco-technology" as a vision needs further elaboration and application. To achieve more general acceptance the vision must be sufficiently matured to be able to offer plausible alternatives and to describe transition pathways, from both economic and technological perspectives, such that the solving capacity is regarded as higher than the existing approach. This will require extensive research, development, and experience ("learning by doing"). Some examples are quantified in table 3.8 (Moser 1996).

Genuine practicality in making suggestions requires detailed knowledge of a particular region or country - its history, culture, biosphere, social structure, manpower situation, etc. There is no single set of recipes for a solution. Only general recommendations can be made, as depicted here.

Nevertheless, the direction seems inevitable. In the long run, principles of life must apply. The imperatives of the long-run survival of the human species surely imply that humans must learn to work within nature - as the so-called "indigenous" peoples had to do rather than treating nature as an enemy to be overcome. This long run survival imperative necessitates the preservation of biodiversity, as well as human cultural and social diversity. In this context, technology becomes a powerful tool to assist us to achieve the sort of eco-restructuring that will be required to achieve long-run sustainability.

Table 3.8 Quantitative data on the reduction of the environmental impact (heco) in the case of some recently elaborated "eco-tech" processes, using the SPI index for the quantification of the production processes (not including the application of the products)

Production process

heco

Drinking water denitrification:

2-5

micro-organisms versus electrodialysis


Bio-pesticides:

10-100

renewable versus fossil raw materials used


Biopolymers:

0.5-3.0

polyhydroxy-butyric acid versus polyethylene


Bio-fertilizers:

>5 104

rhizabium strains as soil bacteria versus chemical synthetic fertilizer (urea)


Notes

1. Technically, genetic engineering involves cutting and splicing molecules of the substance called deoxyribonucleic acid (DNA). The artificially modified forms are known as recombinant DNA or rDNA.

2. Indeed, as of 1994, well over 90 per cent of all worldwide venture-capital funding for biotechnology was targeted at this field of application.

3. See, for instance, the United Nations University's zero emissions research initiative (ZERI) (Paul) 1995).

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