Dr. Joan de Pablo, chemical engineering chair and scientific director of the CTM Technology Center Foundation Environmental Technology Department. Dr. Irene Jubany, researcher and head of Soil for the CTM Technology Center Foundation Environmental Technology Department. Both participated in the workshop organized by Biocat, on 8 June, in Barcelona.
Opinion
Microorganisms, fungi and plants have inhabited the earth for millions of years and have been key to the development of life as we know it on this planet.
The processes that allow these organisms to live entail basic reactions involving both matter and energy. The most well known example is photosynthesis, the transformation of carbon dioxide from the atmosphere into oxygen in plant leaves.
The pressure population growth —now at 6,000 million and increasing— currently puts on the planet is forcing our agriculture and industry to operate sustainably and this undoubtedly generates breakthroughs in biotechnology processes.
Humankind’s use of these processes to benefit the environment has led to the new concept of environmental biotechnology, which the International Society for Environmental Biotechnology (ISEB) defines as “the integration of science and engineering for the development, use and regulation of biological systems for remediation of contaminated environments (land, air, water), and for environment-friendly processes (green manufacturing technologies and sustainable development).”
Although a variety of biological systems can be used in environmental biotechnology, the use of microorganisms is the most common, as they can be managed to provide society with many services. These services range from eliminating toxicity from contaminants in water, soil, sediment and mud through extracting resources from waste. At the same time, they can also be used to derive energy from different types of biomass in its diffuse state, and in some hazardous cases like solid urban waste, creating energy sources directly exploitable by society like biogas (methane and carbon dioxide) and hydrogen.
Microorganisms are able to develop by adapting to practically any environment. Thus, there are microorganisms that can withstand high doses of radioactivity, like those found in cooling pools where used fuel is stored at nuclear power plants, and others that live in environments with high arsenic levels. In order to grow, they need a food source, which, like any living organism, is carbon-based and a source of energy. They obtain energy on a molecular level through electron transfer, which requires a species that can give up electrons to one that can accept them. This simple, and at the same time extremely complicated, process is used in environmental biotechnology to have microorganisms fight contamination, transforming hazardous substances (contaminants) into innocuous substances or ones that are less dangerous, as contaminants are used as a source of carbon, giving up or accepting electrons.
Electron-donor contaminants include petroleum hydrocarbons, biodegradable organic material and ammonium that aerobic microorganisms can transform into carbon dioxide and nitrate. Furthermore, electron-acceptor contaminants (like chromates, arsenates, or urania) can be transformed in anaerobic environments into chemical substances with less atmospheric mobility, and toxic substances (like organochloride solvents) can be made less toxic.
These processes have been applied for many years in urban and industrial wastewater purification processes in order to decrease concentration of organic materials, eliminate recalcitrant organic compounds, eliminate heavy or toxic metals and reduce or eliminate nutrients and pathogens. This has also been applied in the field of contaminating gasses with volatile organic compounds or inorganic sulfur and ammonium compounds, most of which are responsible for the smells associated with water purification plants and trash dumps.
Another important field is the application of biotechnology to contaminated soils and underground water to treat contaminants like petroleum hydrocarbons, polycyclic aromatic hydrocarbons, organochloride solvents, metals and nitrates. These actions can be carried out on site, without removing or extracting contaminated soil or underground water, or ex situ, treating the contaminated material in specific facilities. Passive reactive barriers or stimulation of microorganisms with external carbon sources are examples of on site treatments, while biopile technology, which fosters biological processes in piles of contaminated soil, is an example of ex situ treatment.
However, environmental technology shouldn’t only be used to provide solutions to human contamination problems. One of the challenges this discipline faces is integrating biological processes into production processes in order to minimize resources used and waste generated in order to recover reusable materials and energy from residual currents. With this new view of production processes, we could see residual currents as new materials, resources and energy. This way, we could minimize the extraction of non-renewable resources and energy, maximize the use and regeneration of water, and minimize non-reusable waste.
In order to achieve these goals and improve the applications and use of environmental biotechnology, it is key to implement new tools. Firstly, it must be said that molecular biology allows us to learn about the microorganisms involved, the processes and the relationship between the microorganisms and the environment. Thus, techniques like PCR and FISH must allow us to move forward in knowledge of applied microbiology. Secondly, mathematic modeling of biological processes must be used to design new technology and applications for industry. Finally, and as a third example, life-cycle assessment methodology (LCA) must be employed to quantify environmental improvements of new biotechnology processes in terms of resource use and environmental impact.
In short, environmental biotechnology is a field that requires a multidisciplinary team that must work towards improving industrial processes in order to reduce material and energy resource use and minimize the generation of non-reusable waste, thereby reducing humankind’s impact on the environment as much as possible. All of this through biological systems working to serve society.