Recombinant DNA techniques for bioremediation and environmentally-friendly synthesis

Keasling, Jay D.; Bang, Sang-Weon

doi:10.1016/s0958-1669(98)80105-5

Cited by 26 publications

(10 citation statements)

References 48 publications

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“…However, despite the many advantages of GEMs, there are still concerns that their introduction into polluted sites to enhance bioremediation may have adverse environmental effects, such as gene transfer. A number of new recombinant DNA techniques have been developed for genetically engineered microorganisms for the biodegradation of environmental contaminants or for the synthesis of small molecules (Keasling and Bang 1998). These techniques include new expression vectors to carry the heterologous genes into the host organism, new mechanisms to control gene expression, containment mechanisms to control persistence of geneticallyengineered microorganisms, application of site-directed and random mutagenesis to increase the substrate range or activity of biodegradative enzymes, and methods to track genetically-engineered microorganisms (Keasling and Bang 1998).…”

Section: Genetically Engineered Microorganisms (Gems) and Microbial Smentioning

confidence: 99%

“…A number of new recombinant DNA techniques have been developed for genetically engineered microorganisms for the biodegradation of environmental contaminants or for the synthesis of small molecules (Keasling and Bang 1998). These techniques include new expression vectors to carry the heterologous genes into the host organism, new mechanisms to control gene expression, containment mechanisms to control persistence of geneticallyengineered microorganisms, application of site-directed and random mutagenesis to increase the substrate range or activity of biodegradative enzymes, and methods to track genetically-engineered microorganisms (Keasling and Bang 1998). The application of culture-independent molecular biological techniques also offers new opportunities to better understand the dynamics of microbial communities (Iwamoto and Nasu 2001).…”

Section: Genetically Engineered Microorganisms (Gems) and Microbial Smentioning

confidence: 99%

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A comprehensive overview of elements in bioremediation

Juwarkar

Singh

Mudhoo

2010

Rev Environ Sci Biotechnol

305

128

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Sustainable development requires the development and promotion of environmental management and a constant search for green technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. Bioremediation is an increasingly popular alternative to conventional methods for treating waste compounds and media with the possibility to degrade contaminants using natural microbial activity mediated by different consortia of microbial strains. Many studies about bioremediation have been reported and the scientific literature has revealed the progressive emergence of various bioremediation techniques. In this review, we discuss the various in situ and ex situ bioremediation techniques and elaborate on the anaerobic digestion technology, phytoremediation, hyperaccumulation, composting and biosorption for their effectiveness in the biotreatment, stabilization and eventually overall remediation of contaminated strata and environments. The review ends with a note on the recent advances genetic engineering and nanotechnology have had in improving bioremediation. Case studies have also been extensively revisited to support the discussions on biosorption of heavy metals, gene probes used in molecular diagnostics, bioremediation studies of contaminants in vadose soils, bioremediation of oil contaminated soils, bioremediation of contaminants from mining sites, air sparging, slurry phase bioremediation, phytoremediation studies for pollutants and heavy metal hyperaccumulators, and vermicomposting.

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Section: Genetically Engineered Microorganisms (Gems) and Microbial Smentioning

confidence: 99%

Section: Genetically Engineered Microorganisms (Gems) and Microbial Smentioning

confidence: 99%

A comprehensive overview of elements in bioremediation

Juwarkar

Singh

Mudhoo

2010

Rev Environ Sci Biotechnol

305

128

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“…The absolute confinement of all bacteria in the membrane bioreactor nearly eliminates the release of GEMs in the effluent ( Cicek, Franco et al, 1998 ; Huertas et al, 2003 ) and eliminates risks associated with the release of GEMs into the environment. Nevertheless, it is necessary to track the recombinant DNA to prevent potential escape of antibiotic resistance genes released from recombinant cells and, thus, the membrane system as well as their possible horizontal transfer to other microorganisms ( Keasling and Bang, 1998 ).…”

Section: Introductionmentioning

confidence: 99%

2‐Chlorobenzoate Biodegradation by Recombinant Burkholderia cepacia under Hypoxic Conditions in a Membrane Bioreactor

Urgun‐Demirtas

Stark²,

Pagilla³

2005

Water Environment Research

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The feasibility of applying bacterial hemoglobin technology to degrade 2‐chlorobenzoate (2‐CBA) through co‐metabolism under hypoxic conditions in a membrane bioreactor (MBR) process has been studied in the laboratory. 2‐chlorobenzoate removal and chloride release rates in the MBR system varied from 99 to 78% and 98 to 73%, respectively, depending on the operation conditions. Chemical oxygen demand (COD) removal efficiencies were more than 90% at food‐to‐microorganism ratios ranging from 0.32 to 0.62 g/g/d, and the observed yield was 0.13 to 0.20 g biomass/g COD. The bacterial cell‐floc size‐distribution analysis showed that there is a significant change in bacterial floc size due to high shear stress during operation of the MBR. To characterize growth kinetics of Burkholderia cepacia strain dinitrotoluene, a mathematical model that describes co‐metabolic oxidation of 2‐CBA in an MBR has been developed.

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“…Nevertheless, detailed structural and functional analysis of these proteins has been hampered by the absence of genetic techniques for D. dehalogenans, including transformation, gene cloning, and specific gene disruption and insertion. Moreover, the development of such genetic modification tools would also enable the design of strains with improved performance in the bioremediation of polluted environments (19,35).Host-vector systems that allow for the genetic, metabolic, and protein engineering of low-GϩC gram-positive bacteria (LGB) have been developed and optimized mainly for industrially applied strains of lactic acid bacteria, for bacilli, and, to a lesser extent, for clostridia (for reviews see references (10 to 12 and 41). It has been shown that vectors based on the theta replicon of the broad-host-range conjugative plasmid pAM␤1 (6), among which are the cloning vectors pIL252 and pIL253, are functional in all genera of LGB studied, indicating their potential use for halorespiring genera of LGB, such as Desulfitobacterium and Dehalobacter (12,30).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Development of a Gene Cloning and Inactivation System for Halorespiring Desulfitobacterium dehalogenans

Smidt

Oost

Vos

2001

Appl Environ Microbiol

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Efficient host-vector systems have been developed for the versatile, strictly anaerobic, halo-and fumaraterespiring gram-positive bacterium Desulfitobacterium dehalogenans. An electroporation-based transformation procedure resulting in approximately 10 3 to 10 4 transformants per g of the cloning vector pIL253 was developed and validated. The broad-host-range vector pG ؉ host9 was shown to replicate at a permissive temperature of 30°C, whereas the replicon was not functional at 40°C. The D. dehalogenans frdCAB operon, predicted to encode a fumarate reductase, was cloned, characterized, and targeted for insertional inactivation by pG ؉ host9 carrying a 0.6-kb internal frdA fragment. Single-crossover integration at the frdA locus occurred at a frequency of 3.3 ؋ 10 ؊4 per cell and resulted in partially impaired fumarate reductase activity. The gene cloning and inactivation systems described here provide a solid basis for the further elucidation of the halorespiratory network in D. dehalogenans and allow for its further exploitation as a dedicated degrader.It has been shown for a wide range of haloorganic compounds that reductive dechlorination is the first crucial step in the degradation of such pollutants (15,25). Halorespiring bacteria have received increasing attention during the past decade due to a significant contribution to reductive dehalogenation processes occurring in anoxic polluted environments such as soils, aquifers, and sediments (14,24). In contrast to the cometabolic reductive dehalogenation catalyzed by various metal-containing tetrapyrrol cofactors in a variety of anaerobic bacteria, this reaction is catalyzed at much higher rates by specific enzymes in halorespiring microbes, where it is coupled to energy conservation by electron transport-coupled phosphorylation (14,18,31). One of these strains is the versatile, low-GϩC, gram-positive bacterium Desulfitobacterium dehalogenans, which is able to link the oxidation of several electron donors such as hydrogen, formate, lactate, and pyruvate to the reduction of various organic and inorganic acceptors, including ortho-chlorinated phenols (o-CP), fumarate, and nitrate (37). Recently, the o-CP-reductive dehalogenase (CPR) from D. dehalogenans has been purified and characterized at the biochemical and genetic levels (33,39). Comparison with other chloroalkene-and haloaromate-reductive dehalogenases isolated and characterized from various phylogenetically distinct halorespiring bacteria indicated that these enzymes share significant similarities in both structural and functional properties, suggesting that they constitute a novel class of corrinoidcontaining reductases (for recent reviews, see references 18 and 31).The detailed molecular analysis of the cpr gene cluster in D. dehalogenans led to the identification of genes encoding putative regulatory proteins and protein-folding catalysts, the transcription of which was specifically induced under halorespiring conditions. From these results, their potential involvement in regulation and maturation of t...

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Recombinant DNA techniques for bioremediation and environmentally-friendly synthesis

Cited by 26 publications

References 48 publications

A comprehensive overview of elements in bioremediation

A comprehensive overview of elements in bioremediation

2‐Chlorobenzoate Biodegradation by Recombinant Burkholderia cepacia under Hypoxic Conditions in a Membrane Bioreactor

Development of a Gene Cloning and Inactivation System for Halorespiring Desulfitobacterium dehalogenans

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