What Is Environmental Biotechnology - Research Paper Example

Environmental Biotechnology What are Endocrine Disrupting Compounds (EDCs) and why are they harmful (150- 200 words) Endocrine disrupting chemicals or compounds (EDCs) are substances that can be found in the environment, and consumer products that have the capacity to interfere with hormonal synthesis, metabolic processes and activities resulting in abnormal homeostasis or reproduction (1). The EDCs originate from a wide range of molecules such as EDCs represent a broad class of molecules such as organochlorinated pesticides, fuels, plasticizers, plastics industrial chemicals, and other products that are in widespread use. These chemicals contaminate and pollute bodies of water, and therefore pose grave threat to all life forms, humans included. The contamination of drinking water by these compounds is a major concern, and has led to the development of water treatment strategies aimed at their removal. The EDCs have been implicated in disorders of the neuroendocrine system, specifically on the hypothalamic neurotransmitter system, size of specific hypothalamic region, and the numbers of cells expressing the estrogen receptor β . Certain chemical groups can disrupt and mimic reproductive hormones of fish, resulting in feminisation and premature egg yolk production in fish. Aside from effects on the reproductive system, these disrupters of hormonal activity have also been related to the prevalence of obesity and lately, schizophrenia. 2. What is cylindrospermopsin (CYN) and how can it be detected? (150 -200 words) Cylindrospermopsin (CYN) is a freshwater algal toxin that is produced certain cyanobacterial species. The strains producing CYN are widely distributed in different regions of the world. These are Cylindrospermopsis raciborskii, Umezakia natans and Aphanizomenon ovalisporum. Cylindrospermopsin is a tricyclic alkaloid with a tricyclic guanidine moiety combined with hydroxymethyluracil. It is considered a globally important freshwater algal toxin. The tolerable daily limit for cylindrospermin is 0.02 g/kg body weight/day (2) . Ingestion of CYN can result in liver and kidney damage with bloody diarrhea and urine (2). Several methods have been developed for the detection of CYN (3). CYN has has a maximum UV absorbance at 262 nm, and an easily identifiable peak. The first screening method for CYN used reverse phase high performance liquid chromatography (HPLC) coupled with photo diode array detection.Later HLPC-mass spectrometry with electrospray increased the detection limit to 200 μg L-1. With tandem mass spectrometry, 1 µg of CYB can be detected. The techniques used earlier were quite expensive and the development of polymerase chain reaction amplification systems were developed so with immunochemical techniques such as ELISA kits made detection cheaper and more reliable. 3. What is microbial desulphurization, how does it work? (150-200 words ) Microbial desulphurization is the process wherein the inorganic sulphur in sulphur-containing petroleum and coal fuels are removed through the action of microorganisms that have the capability to break carbon-sulphur bonds. The removed sulphur is water soluble and in inorganic form. Bacteria remove sulfur from dibenzothiophene (DBT), an organosulphur compound, by oxidizing the sulfur atom first, and then cleaving the carbon-sulfur bonds. The end-products of the reaction is 2-hydroxybiphenyl. The most studied bacteria for the desulfurization process is Rhodococcus rhodochrous strain IGTS8, although other bacterial species have been identified to remove inorganic S (4) (5). 4. Discuss the phases in landfill for converting waste into carbon dioxide and methane(150 -200 words) There are five general phases in the conversion of landfills into carbon dioxide and methane (6). The first phase is the adjustment stafe where the biodegradable components of the solid waste are decomposed by microorganisms. At this stage, aerobic microorganisms prevail. Phase II is the transition stage, where oxygen in the landfill is exhausted and the anaerobic conditions start to develop. Nitrate and sulphate are converted to nitrogen gas and hydrogen sulphide. pH of the leachate from the site starts to acidify due to increased CO2 and organic acids. Acid phase develops next as microbial activities result in higher production of acids and reduce the hydrogen gas concentration. At this stage, the high molecular mass components are hydrolysed to smaller compounds for energy utilization by microbials. Biological and chemical oxygen demands increase with the dissolution of organic acids. The fourth is the methane fermentation phase where acetic acids and hydrogen gas are converted by methanogens to methane and carbon dioxide. pH values will increase and the BOD and the COD will decrease. After the methane fermentation phase where the biodegradable material has been converted to gases, the rate of gas generation slows down significantly. At this stage the leachate will contain humic and fulvic acids. Methane will continue to be generated from organic material that biodegrade slowly (e.g. wood). 5. Discuss the limitations on the contribution of environmental biotechnology to industry (Essay – 500 words) The major contribution of environmental biotechnology to industry is in the field of white biotechnology, where native and recombinant microorganisms are employed in industrial processes for producing products for society. Modern biotechnology products are those that were produced with genetically altered microorganisms or organisms. Examples are medicine, antibiotics, hormones, proteins, amino acids, waste management and biofuels. Transgenic plants, like Bt corn and herbicide resistant soybeans, were designed to improve agronomic performance, although these are also used in biopharming to produce pharmaceuticals from plants. Transgenic animals are currently used to express drugs in milk. Biotechnological approaches with use of engineered microorganisms have been used to enhance the yield and diversity of the important compounds amino acids, vitamins, antibiotics and biofuels. Although the potential contribution of environmental biotechnology to industrial process appears to be large, in reality there are many challenges and limitations that need to be overcome before the potential is fulfilled (7). Currently, environmental biotechnology has already made a substantial contribution to industry, but with the advent of more problems, certain limitations need to be addressed. These limitations are mostly aligned with the increase in industrial activity that also resulted in increased waste, increased energy use and higher probability of contamination of the environment. New and more effective strategies for biodegradation and waste management appear to be a major limitation and should be addressed with new engineered enzymes for improved biodegradation, along with the design for new bacterial strains and use of alternative approaches. Wastewater treatment needs to be improved by basing the designs on decentralized systems and reuse of water resources. Anaerobic digestion systems are needed for treating biological wastes, and the development of technology for recycling biowaste to energy. Better and effective approaches are needed for bioremediation of soils that have been contaminated by agricultural activity and mining industries. An important problem is the clean-up of oil spills that contaminate oceans and shores, in order to hasten the rehabilitation of these areas. Biosurfactants from microorganisms that can be produced inexpensively in large amounts are needed by industry for cleaning up oil spills, for converting used cooking oils to biodiesel and for solubilizing pesticide residues to make them easier to remove from contaminated sites. Also, the wide range of pollutants require the development of specific remediation technologies. A case in point is India where rivers are polluted from the byproducts of the drug manufacturing process. Enzymes that can degrade these byproducts are needed. Enzymes for the environmental removal of small chemicals and toxins like the endocrine disrupting compounds and toxins in bodies of water are also needed. Most of the industrial applications of environmental biotechnology are utilized only in first world countries. Developing countries in Europe and Asia do not have access to these technologies, probably due to high cost and lack of knowledge. For these reasons, pollution is common in countries like India and China where industry is advancing, but the use of biotechnological anti-pollution strategies is lagging. Leaders in the field of biotechnology must be more active in bringing the beneficial applications to the poorer countries. Effort needs to be exerted in promoting awareness of techniques that can promote cleaner environments and more sustainable industrial production. 6. Discuss the process and types of soil bioremediation and its advantages and disadvantages (Essay – 500 words) Bioremediation refers to the process where living organisms, specifically microorganisms are used to clean contaminated soil or water. Despite its broad definition, bioremediation usually refers specifically to the use of microorganisms. We plants are used to clean the environment, the process is called phytoremediation. There are three types of bioremediation (8). 1. Biostimulation is the process where nutrients and oxygen are added to the contaminated soil to enhance the growth of the bacteria that is already present in the soil. This is among the easiest type of bioremediation because it involves only minimal intervention. 2. In bioaugmentation, microorganisms that can clean up a specific pollutant are added or brought to the site. This is a good strategy for contaminants that have been introduced to the site. However, the conditions for the optimum growth of the bacteria may not be met, and could result in decline in bacterial population. 3. Intrinsic bioremediation or natural attenuation occurs in sites that have been naturally or slowly contaminated. This type of remediation does not rely on human intervention but on the capacity of indigenous or native bacteria to metabolize the pollutant. However, this approach takes more time. Bioremediation of soils can be performed on site (in situ) or off-site (ex situ). In situ bioremediation does not cause much disturbance to the contaminated site, and incurs less cost than remediation because it does not requires the removal of the contaminated soil. However, this approach is not suited for all soils, and because there is no disturbance, the contact between microorganism and contaminant is not maximized and therefore complete degradation will take more time. Under undisturbed conditions, the conditions for optimal degradation may not be attained. In ex situ bioremediation, contaminated soil is excavated and brought to another site for treatment. Ex situ bioreactors, landfarming and biopiles are utilized to treat the soil. Soil may be mixed in a bioreactor to stimulate the action of microorganisms. In landfarming, the contaminated soil is spread over an area with microorganisms. Aeration is also enhanced in biopiles in order to enhance microbial activity. All the bioremediation protocols are based on the supposition microorganisms are available that have the capacity to degrade the whole range of pollutants. However, in reality, this is not always the case. Contaminants have different composition and therefore would require specific microorganisms for decomposition. Although microorganisms can develop mechanisms for metabolizing certain chemical constituents, but this will only happen over a long period of time. Also, removing microorganisms from their natural habitats and transferring them to another site to work as decomposers will affect their efficiency because they need time to adjust to newer conditions. All bioremediation strategies require the monitoring of the levels of the metabolites and the gases that are released into the environment during the decomposition process. In order for bioremediation strategies to be successful and sustainable, more research should be conducted towards the discovery and development of efficient microorganisms for cleaning up the environment. It is also important to conduct collection and screening of the culturable microorganisms and their essential properties that can be exploited for bioremediation. 7. How environmental biotechnology can be used for the production of energy (Essay – 500 words) Environmental biology is the utilization of microbial communities to provide products and services to society. The role of microorganisms in production of energy from wastes and other natural resources is very important now in the face of increasing prices and declining supplies of fossil fuels. Microorganisms can convert various types of biomass from its many forms to energy sources like methane, electricity, ethanol and biodiesel. Methanogens are a group of microorganisms than can degrade organic matter and release methane and carbon dioxide. The released methane can be trapped and diverted for domestic use as fuel in lieu of electricity or liquefied petroleum gas. Currently efforts are underway to select bacteria and bacterial genes for efficient methane production. Another area of research now is to screen for microbial organisms that can produce cellulase, hydrolyse cellulose and promote fermentation for the conversion of cellulosic biomass to fuels in just one step (9). This process, named consolidated bioprocessing or CBP is the approach used to revolutionize energy production from biomass. Microorganisms with the three properties are being developed through genetic engineering of celluloytic microbes for the improvement of their yields, and on the other hand, genetically engineering vigorous non-celluloytic microorganisms to encode a cellulase system. The traditional method is to screen the natural habits for microbial species for strains that naturally have these desired traits. Another interesting development is the microbial fuel cell (MFC) that provides new opportunities for the sustainable energy production from biodegradable compounds. These MFCs are biological electrical reactors where microorganisms mediate the conversion of the chemical energy in organic matter or biomass to electrical energy. The MFCs act on different carbohydrates, and other complex substrates that can be found in wastewaters. These include low molecular weight acids, starch, cellulose, chitin and different types of wastewaters. However, there is only limited information about the metabolic properties and the nature of the bacteria in the microbial fuel cells. Bacteria are placed in the anode chamber together with their substrate. When the bacteria degrades the organic matter the released hydrogen gas and CO2 are used to generate electricity in the cathode chamber. Metabolic engineering of microorganisms is also an important contribution of environmental biotechnology towards the development of newer and cleaner fuels (10). With increase in global need for energy, and with the emergence of environmental problems, efforts have been stepped up towards the synthesis of liquid biofuels for transportation sector energy. Advanced biofuels should have better qualities that the traditional bioethanol like higher energy density, lower vapour pressure and must be compatible with existing transportation infrastructure. However, since such fuels cannot be synthesized with the help of the native and currently available microorganisms. Environmental biotechnology techniques in metabolic engineering will help in developing microorganisms that can produce these ideal fuel molecules. E. coli strains are being metabolically engineered to meet the production needs for these ideal fuels. Aside from the state-of-the-art metabolically engineered microorganisms, there are already microbial strains that are being employed in the processing of biofuels from biomass, corn kernels, algae, sugar crops, and oil nuts. References 1. Endocrine Disrupting Chemicals: an Endocrine Society Scientific Statement. Kandarakis, E, et al. 2009, Endocrine Reviews, Vols. 30(4):293-342. 2. Masten, S. Cylindrospermopsin: Review of Toxicological Literature. Research Triangle Park, North Carolina : National Institute of Environmental Health Sciences, 2000. 3. Cylindrospermopsin: a decade of progress on bioaccumulation research. Kinnear, S. 2010, Marine Drugs, pp. 8:542-564. 4. Characterization of the desulfurization genes from Rhodococcus sp strain IGTS*. Denome, S, et al. 1994, Journal of Bacteriology, Vols. 176(21):6707-6716. 5. Sulfur-Specific Microbial Desulfurization of Sterically Hindered analogs of dibenzothiophene. Lee, M, Senius, J and Grossman, M. 1995, Applied and Environmental Microbiology, Vols. 61(12):4362-4366. 6. Solid waster management: newt rends in landfill design. Warith, M. 2003, Emirates Journal for Engineering Research, Vols. 8(1):61-70. 7. Environmental biotechnology: acheivements, opportunities and challenges. Gavrilescu, M. 2010, Dynamic Biochemistry, Process Biotechnology and Molecular Biology, pp. 4(1):1-36. 8. Bioremediation. BioBasicss. [Online] July 9, 2008. [Cited: July 27, 2011.] http://www.biobasics.gc.ca/english/View.asp?x=741. 9. Consolidated bioprocessing of cellulosic biomass: an update. Lynd, L, et al. 2005, Current Opinion in Biotechnology, pp. 16:577-583. 10. Metabolic engineering for advanced biofuels production from Escherichia coli. Atsumi, S and Liao, J. 2008, Current Opinion in Biotechnology, Vols. 19(5):414-419. 11. Sasson, A. Industrial and Environmental Biotechnology: Achievements, Prospects, and Perceptions. s.l. : United Nations University, Institute of Advanced Studies, 2005. 12. Microbial fuel cells: novel biotechnology for energy generation. Rabaey, K and Verstraete, W. 2005, Trends in Biotechnology, Vols. 23(6):291-298. Read More