The environment around us has always been a source of new products and stimulated our imagination in developing new technologies. Our species is very successful at harnessing the environment for our benefit. We are also good at destroying or harming the environment for immediate gains. The readily visible world has been charted and mapped, but areas under the ocean and in the deep recesses of jungles are still unknown. In fact, many parts of the visible world still harbor unknown life forms invisible to the naked eye, including bacteria and viruses. These are found in the air, water, and land. Many have unique metabolisms, and some have abilities never seen before. Many can live in extreme environments, once thought too hot or too dry for life to exist.
Estimates predict that about 1031 to 1032 viral particles are present in the biosphere, an order of magnitude more than host cells. The virosphere, as it is sometimes known, is probably one of the biggest sources of novel genes. At the time of writing, only about 0.1% to 1% of microorganisms have been cultured. Even the majority of those found growing at moderate temperatures in soil or other normal habitats have not been cultured. In addition to DNA inside life forms, there is much free DNA in the environment that might also be a source of new genes. The field of environmental biotechnology has revolutionized the study of these previously hidden life forms and DNA. What kinds of secrets do they harbor? What kinds of new enzymes and proteins can be identified?
Molecular biology techniques are now being applied directly to the environment to investigate the uncultured viruses and bacteria. PCR is routinely used to amplify random sequences from many environmental samples in the hope of identifying new genes. After PCR, the DNA is sequenced. Then bioinformatics reveals whether or not the sequence (or a close relative) has already been identified or if it is completely novel. Microarrays are also being created to compare the numbers and types of organisms present in different environments. Almost every recombinant DNA methodology discussed in the first half of this book can be applied to environmental samples.
Environmental biotechnology is divided into different areas. These include direct studies of the environment, research with a focus on applications to the environment, or research that applies information from the environment to other venues. This chapter focuses on direct analyses of the environment and the natural biochemical processes that are present, whereas upcoming chapters cover research with environmental applications or results from environmental research with practical applications. Surveying different environments may identify new life forms, new metabolic pathways, or novel individual genes. Genomics techniques have revolutionized this field, and it is rapidly expanding.