Bioremediation of organic contaminants

Biopract provides technological products and processes for industry, agriculture, and environment. They not only produce technical enzyme preparations but also develop enzymes for applications in agriculture, food, and textile industry as well as in environmental technologies. On the later, bioremediation has been an area of service delivery from Biopract. Their activities regards microbial preparations for the bioremediation of organic contaminants (mineral oil (MKW), polycyclic aromatic hydrocarbons (PAH), benzene, toluene, ethylbenzene, xylene (BTEX), methyl-tert-butyl ether (MTBE), volatile organic hydrocarbons (VOC), and dimethyl sulfoxide (DMSO)). 

Electrokinetic transport is a patented, in situ, commercially available technology for the bioremediation of organic contaminants in aquifer soils and groundwater. The technology involves the application of a direct electrical current across the area to be treated to facilitate the movement of biodegrading bacteria to the site of contamination. 

Microbial cleaners (MCs) are a mixture of specially selected microorganisms and biocatalysts designed for the bioremediation of organic contaminants in soil or water. According to the vendor, MCs have been used in multiple full-scale applications and are commercially available from EnviroLogic Engineering. 

The engineered bioremediation system (EBS) is a proprietary process for the ex situ bioremediation of organic contaminated soils. The system is designed to enhance the natural bioremediation rate of organic constituents by controlling factors affecting microbial growth and metabolism. 

Limnofix In situ Sediment Treatment (LIST) technology is offered by Limnofix, Inc., a Colder Associates Company. The technology allows for the in situ treatment of contaminated sediment in surface waters. LIST enhances bioremediation of organic contaminants oxidizes sediments to control odor, nutrient release, or sulfide toxicity and produces stable marine sediment surfaces via consolidation and flocculation. 

Hickman, Z.A. and Reid, B.J. 2008. Earthworm assisted bioremediation of organic contaminants. Environment International, 34 1072-81. 

Bouwer, E. J. (1992) Bioremediation of Organic Contaminants in the Subsurface, in Environmental Microbiology, R. Mitchell, Ed., Wiley-Liss, New York, pp. 287-318. 

COUPLING ELECTROKINETICS TO THE BIOREMEDIATION OF ORGANIC CONTAMINANTS PRINCIPLES AND FUNDAMENTAL INTERACTIONS... 

Wick LY (2009) Coupling electrokinetics to the bioremediation of organic contaminants principles and fundamental interactions. In Reddy KR, Cameselle C (eds) Electrochemical remediatirai technologies for polluted soils, sediments and groundwater. Wiley, Hoboken, pp 369-387... 

Scow KM, Hicks KA (2005) Natural attenuation and enhanced bioremediation of organic contaminants in groundwater. Curr Opin Biotechnol... 

Bouwer EJ (1992) Bioremediation of organic contaminants in the subsurface. In Mitchell R (ed) Environmental microbiology. Wiley, New York, pp 319—333 Brandi H, Gross RA, Lenz RW, Fuller RC (1988) Pseudomonas oleovorans as a source of poly(P-hydroxyalkanoates) for potential application as biodegradable polyesters. Appl Environ Microbiol 54 1977—1982 Breslin VT (1993) Degradation of starch-plastic composites in a munidpal solid waste landfiU. J Environ Polym Degr 1 127—141... 

Considerable interest has been expressed in the chlorophenol-degrading organism Mycobacterium chlorophenolicum (R. chlorophenolicus) (Apajalahti et al. 1986), partly motivated by its potential for application to bioremediation of chlorophenol-contaminated industrial sites (Haggblom and Valo 1995). 

The extent of bioremediation of sediments contaminated with PCBs appears to be limited by the association of a significant fraction with organic components of the sediment phase (Harkness et al. 1993). 

TCE is not able to support the growth of a single organism, but it is susceptible to cooxidation by oxygenases elaborated by organisms dnring growth with structurally unrelated substrates. A review of methanotrophic bacteria (Hanson and Hanson 1996) contains a useful account of their application to bioremediation of TCE-contaminated sites. 

Sandrin, T. and Hoffman, D., Bioremediation of organic and metal co-contaminated environments Effects of metal toxicity, speciation, and bioavailability on biodegradation, in Environmental Bioremediation Technologies, Singh, S.N. and Tripathi, R.D., Eds, Springer, Berlin, Germany, 2007, pp. 1-34. 

Bioremediation is not restricted only to biodegradable organic contaminants. New techniques are currently under development for the bioremediation of metal-contaminated sites. Microbial activity can alter the oxidation state of some elements, reducing or increasing their mobility, and this transformation can be used for remediation purposes. 

Bioremediation is a technique for treating zones of contamination by microbial degradation, which involves altering the environmental conditions to enhance microbial catabolism or cometabolism of organic contaminants, resulting in the breakdown and detoxification of those contaminants.15 According to microbial metabolic activity, bioremediation can be classified into three categories20-21 ... 

The use of vegetable oil for remediation of organic contaminants in an aquifer or unsaturated zone has been smdied at Pacific Northwest Laboratory. The oil strips organic compounds from the aqueous phase or particulate matter and is then pumped out for recovery. In addition, the oil can be used as a carbon source by microorganisms, hence encouraging in situ bioremediation. The technology has not proceeded beyond bench-scale testing and is not commercially available. 

Bearehaven Reclamation, Inc. (Bearehaven), in situ bioremediation is a proprietary technology for the treatment of organic contaminants. According to the vendor, the process can readily remediate trichloroethylene (TCE), polychlorinated biphenyls (PCBs), diesel fuel, and other more complex organic compounds in soil, water, sludge, and landfills. 

Pool Process electrokinetic remediation (Pool Process) is a patented, commercially available technology for the removal of heavy metals and other ionic contaminants. The technology uses a series of electrodes placed in contaminated media to recover ionic contaminants in situ or ex situ from soils, muds, groundwater, dredgings, and other materials. The Pool Process can also be used to enhance bioremediation of media contaminated with a combination of ionic and nonionic organic contaminants. 

The SBP slurry-phase bioremediation system can treat a wide range of organic contamination, especially wood-preserving wastes and solvents. A modified version can also treat polynuclear aromatic hydrocarbons (PAHs) such as creosote and coal tar pentachlorophenol (PCP) total petroleum hydrocarbons (TPH) and chlorinated aliphatics, such as trichloroethene (TCE). The technology can be combined with SBP s membrane filtration system to form a soil cleaning system to handle residuals and contaminated liquids. 

Trans Coastal Marine Services (formerly Envirosystems, Inc.) and Louisiana State University (LSU) have developed several bioreactor systems to facihtate petroleum hydrocarbon mineralization and the bioremediation of organic wood preservatives utilizing an immobilized microbe bioreactor (IMBR) technology. These technologies can treat petroleum hydrocarbons, chlorinated solvents, pesticide-contaminated soils, and contaminated groundwater. 

Phosphate-induced metals stabilization can be used for the remediation of metals in mixed waste streams concurrently with other remediation technologies such as vapor stripping or bioremediation of organics. Using apatite to treat soils contaminated with lead, cadmium, and/or zinc can significantly reduce the amount of metals leached from the soil. The amount of apatite needed for treatment is less than 1% by weight. The reaction between metals and apatite is immediate, and the apatite can be heavily loaded with metals. 

One of the major obstacles in bioremediation of soils contaminated with synthetic organic compounds is the failure of laboratory remediation schemes to simulate the impact of field soil conditions on both the contaminant and the microorganism (Rao et al., 1993)- The purpose of this chapter is to introduce those topics which must be considered in order to develop an effective bioremediation strategy for soils contaminated with organic pollutants. My emphasis is on providing a comprehensive overview of the complexity of the soil system as it relates to bioremediation. 

The interaction of bacteria with solid surfaces including soil may have a variety of indirect and direct impacts on the cell (van Loosdrecht et al., 1990). Direct impacts result from changes in microbial membranes (e.g., permeability to various substrates) resulting from a surface interaction. Indirect impacts related to microbial activity are a result of modification of the immediate environment of the cell (e.g., alteration of substrate availability) (Harms Zehnder, 1994). The influences of soil colloids on general microbial processes (Stotzky, 1986) and biodegradation kinetics of organic contaminants (Scow, 1993) have been summarized. However, two areas specifically pertinent to bioremediation will be described. 

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