Microorganisms are ubiquitous and they play several roles in the degradation of recalcitrant organic and inorganic materials in the environment. The degradation of these materials that constitute environmental hazards in the environment can be carried out under aerobic and anaerobic conditions; and these processes leads to the production of several environmentally-friendly substances and compounds that are of industrial or economic importance including carbondioxide (CO2), methane, hydrogen sulphide (H2S) and water. Microbes are significant in biodeterioration activities because they produce enzymes which are used for the enzymatic breakdown of these organic and inorganic materials that litter the environment.
Biodeterioration is defined as the deterioration (spoilage) of an object or material as a result of biological activity (usually microbial activity). It is the undesirable change in the physical and/or chemical properties of a material that is caused by the activities of living or biological organisms including microbes. During this process, the microbes encourage the reduction or loss in the quality or value of the material through their several metabolic activities. Examples of materials prone to the biodeterioration mediated by microbes include paper, petroleum, rubber, textiles, glass, leather, food, coal, paint, wool and timber. Microbial activities can lead to food spoilage, spoilage of fuels and oils, spoilage of glass, timber, cultural heritages, textiles, paper, timber and spoilage of textiles, coal, wool and leader. The term biodeterioration is synonymous with biodegradation.
Biodegradation is defined as the degradation of a substance or material as a result of biological (usually microbial) activity. Biodeterioration and biodegradation activities could be of importance to the environment because they could help in recycling of nutrients or organic matter in the environment irrespective of the fact that these processes lead to the deterioration of materials as aforementioned. Most importantly, biodegradation is often used to describe those human activities that harnesses the decaying or saprophytic activities of microbes including bacteria and fungi in such a way that waste materials could be transformed and made more useful and acceptable to man and his environment.
Fungi and bacteria are important agents in biodeterioration and/or biodegradation activities; and these microbes grow on the materials especially in warm or humid environmental conditions and thus mediate the spoilage of the material or substance through their diverse metabolic activities. For example, certain fungi including Aspergillus fumigatus, Penicillium species, and Cladosporium species can grow on the surfaces of glass (such as the lenses of microscopes) during humid or warm environmental conditions. These microbes can derive their nutrients for growth from several sources. They could derive their growth nutrients from the adjacent substrates around the microscope lenses such as compounds used for sealing the lenses or from films (biofilms) of materials that condensate and collect on the glass surface. As the spoilage fungi grow and metabolize the substrates, it produces extracellular products or metabolites that etch the surfaces of the glass; and this will affect or reduce the quality and/or value of the glass.
Nevertheless, the spoilage of glass can be prevented by using fungicides to disinfect the glass surfaces or by storing the glasses under dry environmental conditions. Effective and repeated cleaning of the glass surfaces after use and/or during storage can also prevent its deterioration by the spoilage fungi. Biodegradation is simply nature’s way of recycling wastes, or breaking down organic matter into nutrients that can be used and reused by other organisms including man. But from the microbiological point of view, biodegradation simply means that the decaying of all organic materials is carried out by a complex and diverse community living organisms that comprise mainly bacteria and fungi, and other organisms.
Biodegradation activities mediated by microbes transform hazardous toxic chemicals into non-toxic or less toxic substances that are beneficial to man, plants, animals and the environment. Since virtually all waste material get recycled by nature through biological (microbial) activities), there is hardly any waste in the environment; and this supports the view that the metabolites produced by one organism may serve as the growth nutrients for other groups of organisms. The harnessing of the biodegradation potentials of microbes is the brain behind most recycling and degradation activities carried out by man in the environment especially those that have to do with waste water treatment, sewage treatment and bioremediation of oil-contaminated soils or environment.
The cleanup of organic and inorganic wastes in the environment could be achieved when the biodegradation potential of microorganisms are harnessed. Most wastes materials contain compounds that encourage microbial growth. For example, crude oil and other oil products contain hydrocarbon, nitrogen, potassium, phosphorus, water and other environmental conditions such as pH, and temperature that modulate microbial growth. Thus microorganisms that have high affinity for hydrocarbons such as Pseudomonas species use the nutrients present in the contaminant for their growth, and this leads to the formation of an ecological niche that supports the thriving of more hydrocarbon-oxidizing bacteria that aid the cleanup process. Microbial degradation of organic and inorganic compounds in the environment including pesticides is an important economic process that help to rid the environment of wastes; and it also provide the opportunity for some of these wastes to be recycled and reused for other commercial processes especially when the degradation activities of microbes are intentionally harnessed to achieve this. Irrespective of their obvious small sizes, microorganisms play several significant ecological roles in the natural environments.
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