Microbial biodegradation

About: Microbial biodegradation is a research topic. Over the lifetime, 1647 publications have been published within this topic receiving 75473 citations.

Microbial degradation of polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocyclics

Abstract: Fermentor studies were conducted to examine the microbial degradation of polycyclic aromatic hydrocarbons (PAHs; naphthalene, phenanthrene, anthracene) and a polycyclic aromatic nitrogen heterocyclic (quinoline) using a mixed bacterial culture capable of utilizing these compounds as the sole carbon and energy source for growth. Half-lives for the three PAHs in the cyclone fermentor system ranged from 1 day for naphthalene to 4 days for anthracene. Several major metabolites during the biodegradation of PAHs were also identified. These included 2-hydroxybenzoic acid and 1-naphthalenol (for naphthalene); 1-phenanthrenol and 1-hydroxy-2-naphthalenecarboxylic acid (for phenanthrene); and 3-hydroxy-2-naphthalenecarboxylic acid (for anthracene). Thus our bacterial culture biodegraded the three PAHs by initial hydroxylation of the molecule followed by the eventual cleavage of the ring to yield the ortho- or meta-cleavage intermediates, which would be further metabolized via conventional metabolic pathways. However, biodegradation of the nitrogen-containing polycyclic aromatic hydrocarbon compound quinoline by our culture resulted in the accumulation of 4–5 metabolites, one of which has been identified as 2-quinolinol. Work is in progress to identify the other metabolites from quinoline degradation. © 1992 John Wiley & sons, Inc.

Developing strategies for PAH and TCE bioremediation

Abstract: Bioremediation is the controlled use of microbes, commonly bacteria and fungi, to reclaim soil and water contaminated with substances that are deleterious to human health and the environment. The organisms used often naturally inhabit the polluted matrix; however, they may inhabit a different environment and be used as seed organisms because of their ability to degrade a specific class of substances. It is because of the wide diversity of microbial metabolic potential that bioremediation is possible. Polyaromatic hydrocarbons (PAHs) are organic compounds that are ubiquitous in the environment. They are present in fossil fuels and are formed during the incomplete combustion of organic material. PAHs exhibit low volatility and low aqueous solubility. As the molecular weight of these compounds increases, there is an exponential decrease in solubility and volatility. PAHs tend to adsorb onto soils and sediments because of their hydrophobic character, which is an intrinsic function of molecular size. The microbial degradation of individual PAHs by pure cultures and mixed populations occurs under a wide range of soil types and environmental conditions. Generally, the factors having the greatest influence on PAH biodegradation rates are soil moisture content, pH, inorganic nutrients present, PAH loading rates, initial PAH concentrations, and themore » presence of an acclimated microbial population. Feasibility studies are essential for developing a bioremediation strategy and are performed in a phased testing program that is designed to accomplish a number of objectives. These objectives include establishing an indigenous microbial population that will degrade specific contaminants, defining the rate-limiting factors for enhanced PAH degradation and the optimal treatment in terms of rates and cleanup levels attainable, and developing design parameters for field operations.« less

Biodegradation of polythene and plastic by the help of microbial tools: a recent approach

Abstract: Microorganism play a significant role in biological decomposition of materials including synthetic polymers in natural environments, this is called biodegradation. In this review microbial biodegradation of polythene and plastics are discussed. Here we aim to isolate and identify microorganism associated with various polyethylene and plastic degradation in the soil. Polythene and plastic are the two polymers with wide ranging applications. They are recalcitrant and hence remain inert to degradation and deterioration leading to their accumulation in the environment, and therefore creating serious environmental problems. In this context, an attempt was made to study the biodegradation of polythene and plastic strips inside the laboratory (under controlled condition) and outside the laboratory (under natural condition) with the help of microbial tools. In this review, biodegradation of these two polymers under in vitro conditions is reported. An attempt has been made to cover the mechanism of biodegradation, the various bacterial and fungal organisms that have been reported for the same, method adopted for the studies and different characterization techniques followed to measure the extent of degradation.

Microbial Bioconversion of Pollutants

Abstract: Rapid development of industry and agriculture has led to the continuous inflow of ever-increasing amounts of various synthetic compounds, many of which have carcinogenic, toxic and mutagenic properties. Some of these pollutants are rather persistent in the environment and yield slowly to microbial conversion. Accumulation of these pollutants in the biosphere may create ecological stress which is frequently the cause of regional or global contaminations. These pollutants may also be hazardous to human health. One of the major solutions is total destruction of persistent pollutants followed by release of their intermediates into the biospheric cycles. This requires that technologies be developed which would provide the total detoxication and mineralization of industrial wastes to prevent the unintentional release of toxic pollutants into the environment. A major role in the involves microbial methods of xenobiotic detoxication. In recent years, great attention has been paid in this country to the development of waste-free technologies, use of microorganisms for detoxication of various pollutants, and working out the microbial methods of cleanup for various plants.