Environmental biotechnology is a new interdisciplinary subject combining modern biotechnology and environmental engineering. It is a biotechnology that uses a certain part of the biosphere to control the environment or control pollutants scheduled to enter the biosphere. Environmental biotechnology in a broad sense covers a wide range, and all biotechnology-related technologies involved in environmental control in the natural environment can be classified as environmental biotechnology. Including the bioremediation of pollutants in the environment, the bioremediation of contaminated sites, the development and application of harmless and pollution-free biological products such as biodegradable materials, etc. [ 1].
Two. Application of modern biotechnology in the field of environmental protection
With the rapid development of modern industry and agriculture, the wide application of agricultural chemicals, the vigorous development of energy and the further expansion of urbanization, especially the rise of township enterprises in recent years, many new chemical, physical and biological substances have appeared in the environment, such as genetically modified organisms and enzyme products. These new substances may bring new adverse effects to the environment on which human beings depend. The emergence of environmental problems, such as complicated pollutants, increasingly serious pollution and decreased biodiversity, makes it inevitable that modern biotechnology will be widely used in the field of environmental protection. At present, the application of modern biotechnology in the field of environmental protection is generally manifested in four aspects: environmental monitoring and evaluation, pollution elimination, comprehensive utilization of energy resources, saving endangered species and protecting biodiversity.
1. Environmental monitoring and assessment
The application of modern biotechnology, such as enzyme-linked immunosorbent assay, PCR, electron microscope, gene differential display, biosensor, gene probe, biochip and so on, to monitor and evaluate the environment has become a hot spot for scientists at home and abroad in recent years, and the number of research reports is increasing day by day [2-4]. The application of enzyme-linked immunosorbent assay (ELISA) to detect and analyze pesticides and their metabolites in the environment is a new technology in the 1990s. At present, enzyme-linked immunosorbent assay methods for pesticides, fungicides, herbicides, PCBs, dioxins, antibiotics and other pollutants have been developed at home and abroad, and enzyme-linked immunosorbent assay kits for rapid on-site analysis have been commercialized. This technique has the advantages of rapidity, sensitivity, low cost, strong specificity and suitability for on-site analysis of a large number of samples.
PCR technology can be used to detect pathogenic bacteria and indicator bacteria in soil, water and air. Niedrhauser[3] and others used PCR technology to detect Listeria monocytogenes in food, which is easy to cause human meningitis. The analysis of this strain by PCR technology can be completed in just a few hours, which greatly shortens the analysis period (the traditional method takes at least 10 day). Moreover, PCR technology can also track and detect genetically engineered bacteria beads (GEMs) in the environment, determine gene expression according to the diagnosis of gene sequence, and detect specific people in the environment [6]. With the development of PCR technology, nested PCR, reverse PCR and multiplex PCR have been established [7]. It can be predicted that PCR technology will play an increasingly important role in detecting pathogenic bacteria, indicator bacteria and genetically engineered bacteria in water, soil and other environments.
In recent years, the use of biosensors to monitor pollutants in the environment, especially on-site monitoring, has attracted more and more attention. The biosensor consists of a molecular recognition unit (sensitive material) and a conversion part (transducer), and the molecular recognition part is used to recognize the measured target. According to the different sensitive materials, it can be divided into enzyme sensor, microbial sensor, cell sensor and immune sensor. At present, biosensors have reached the level of commercial application: BOD biosensor, ammonia biosensor, nitrite biosensor, ethanol biosensor, methane biosensor and so on. [8-9]. The use of biosensors has the advantages of low cost, easy manufacture, convenient use, rapid determination and time saving, and has attractive prospects in environmental monitoring.
2. Eliminate pollution and improve the ecological environment
Modern biotechnology is often used to eliminate pollution and improve the ecological environment. Including biological reduction of environmental pollutants and biological restoration or restoration of contaminated sites [10]. In the early 1960s, Martin Alexnder[ 10] studied the biodegradability of pesticides in soil, which laid the foundation for the application of biotechnology in the field of environmental protection. Since 1970s, it can be said that biotechnology has developed rapidly, and its application in environmental pollution control has become more and more extensive. This momentum has continued to this day. At present, the research and application of biotechnology in this field has moved towards finding, separating and screening microbial species and strains with high purification ability and artificially constructing genetically engineered bacteria. Through genetic engineering, using plasmid DNA recombination and plasmid transformation, pollutants-resistant organisms can be cultivated. If someone puts the genomes of four kinds of Pseudomonas into the same strain and creates a superbug with extraordinary ability to degrade oil, it can degrade two-thirds of hydrocarbons in the oil slick in a few hours, while it takes more than one year to use natural bacteria [7]. Chakabrty et al. transferred OCT plasmid and mercury-resistant MER into pseudomonas putida at the same time, so that it could degrade alkanes, grow in an environment containing 50-70mg/L mercury, and degrade organic mercury. American scientists transferred the gene containing herbicide 2,4-D from one bacterium to another fast-growing bacterium, which obviously accelerated the degradation of 2,4-D [1 1]. At present, bacteria capable of degrading petroleum and its derivatives such as camphor, pesticides such as bhc, chemical pollutants such as nylon oligomer and heavy metals such as mercury have been cultivated through biotechnology. At the same time, transgenic plants that can absorb and accumulate heavy metals excessively, especially hyperaccumulator plants [12], are also the focus of current research and development. The application of phytoremediation can not only purify and beautify the environment, but also process and reuse it through collection.
3. Develop clean energy and resources and their comprehensive utilization.
The dependence and utilization of energy make people feel the limitation and potential crisis of non-renewable energy, and the development of modern biotechnology brings new hope to solve this problem. Today, the concept of biotechnology also extends to the elimination of harmful substances and wastes and the transformation and reuse of these substances. Such as the production of single cell protein (SCP) from waste and the production of alcohol from cellulosic materials. German used xylose to produce edible yeast, and later used sulfurous acid waste liquor from paper industry to develop feed yeast, with an annual output of 65.438+0.5 billion tons of single-cell protein as meat substitute, which supplemented the shortage of protein. Scientists in China used monosodium glutamate wastewater to produce Candida tropicalis single cell protein, containing 60% of protein. This product is used as feed with the same effect as fish feed [1]. A company in London, England, used Bacillus stearothermophilus, an "engineering bacterium", to convert wastes such as straw and corncob into ethanol, and its efficiency was obviously higher than that of yeast [13].
In the aspect of new energy, the Institute of Genetics of Chinese Academy of Sciences and China Academy of Agricultural Sciences have transferred the gene degrading herbicide triazene into soybean plants, and transgenic soybeans no longer absorb triazene in the environment. Using this technology, green food beneficial to human safety can be produced. Swiss and American scientists have developed a new type of solar cell based on the physiological and biochemical principles of plants. At the same time, other new energy sources, such as algae power generation, bioflocculant, biosurfactant, PHAs and biological pesticide, have also been developed and applied.
4. Save endangered species and protect biodiversity.
Biodiversity refers to the diversity and variability among organisms and the ecological complexity of species habitats, including genetic diversity, species diversity and ecosystem diversity [14]. The rapid development of industrialization and modern science and technology has brought great changes to the earth, which has pushed many species to extinction. However, with the gradual maturity of "cloning" technology, endangered species can continue and it is completely feasible to protect biodiversity. In fact, since Dolly Lamb was born, many scientists began to clone endangered species. For example, scientists from the Institute of Aquatic Sciences and the Institute of Zoology of China Academy of Sciences are making preparations for cloning baiji and giant panda in the future, and have achieved initial results. At the same time, modern biotechnology will greatly increase the number of agricultural products per unit area, reduce the pressure of over-utilization of biological resources, and alleviate the reduction of biodiversity to a great extent.
The development of biotechnology will cultivate crop varieties with strong disease resistance, without as many pesticides and fertilizers as traditional varieties, and reduce the impact of environmental pollution brought by agricultural production on the ecosystem. In addition, new agricultural biotechnology, such as pest control, grass control and bacterial control, can reduce the amount of pesticides, which is also conducive to maintaining the biodiversity of the ecosystem.
Third, the potential impact of modern biotechnology on the environment.
The emergence of a new technology will often have an unprecedented impetus and far-reaching impact on the development of human history. At the same time, there may be unknown consequences or risks, especially when human beings can't ensure the correct and effective use of technology, the disaster it causes will be shocking. Biotechnology, as a high-tech that has been rapidly developed and applied in the environmental field, is no exception. It has both advantages and disadvantages. While creating remarkable economic, social and environmental benefits, there are also environmental security problems. In fact, biotechnology does have a negative impact on the environment. For example, feeding mice with potato containing snowdrop lectin (GNA) gene led to abnormal organ growth and destroyed the immune system, and the butterfly incident in which 44% of butterflies died after feeding Bt transgenic corn. Since the emergence of genetic engineering in the 1970s, people have paid great attention to the safety of biotechnology activities and their products to human beings and the environment [15- 16], and genetic engineering is the focus of debate.