Effects of Culture Conditions on Enhancement of 2,4‐Dinitrotoluene Degradation by <i>Burkholderia</i>Engineered with the <i>Vitreoscilla</i> Hemoglobin Gene

Nasr, Mohamed A.; Hwang, Kwang-Woo; Akbaş, Meltem Yeşilçimen; Webster, D. R.; Stark, Benjamin C.

doi:10.1021/bp000152y

Cited by 29 publications

(23 citation statements)

References 21 publications

(25 reference statements)

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“…As mentioned above, the effects of aeration rate, initial 2,4-DNT concentration, and concentration and type of cosubstrate on the degradation of 2,4-DNT by Burkholderia strains DNT and YV1 were investigated in batch culture experiments [Lin et al, 2003;Nasr et al, 2001;. Contrary to the report of Spanggord et al [1991], we were unable to demonstrate that either strain DNT or YV1 can grow on 2,4-DNT (100 M ) as the sole carbon source.…”

Section: Cometabolism Of 24-dnt By Burkholderia Strains Dnt and Yv1contrasting

confidence: 76%

“…Contrary to the report of Spanggord et al [1991], we were unable to demonstrate that either strain DNT or YV1 can grow on 2,4-DNT (100 M ) as the sole carbon source. 2,4-DNT degradation increased, however, with increasing cosubstrate concentration and was generally greater for strain YV1 than strain DNT for a variety of cosubstrates, cosubstrate concentrations and aeration rates; the greatest advantages of YV1 (up to 3.5-fold) occurred under limited aeration conditions [Nasr et al, 2001]. Similarly, both strains DNT and YV1 degraded over 99% of a starting concentration of 217 mg/l 2,4-DNT when yeast extract was used as the primary carbon source in the culture medium .…”

Section: Cometabolism Of 24-dnt By Burkholderia Strains Dnt and Yv1mentioning

confidence: 90%

“…The following study, in which Burkholderia strain DNT was engineered to produce VHb, showed a more substantial benefit regarding biodegradation of 2,4-dinitrotoluene (2,4-DNT) [Patel et al, 2000]. Further studies with the Burkholderia system showed that the VHb-related enhancement occurs in a variety of media, and is relatively greater under hypoxic compared with higher aeration conditions [Nasr et al, 2001]. This work was followed by experiments demonstrating a direct stimulation by VHb of the first enzyme in the Burkholderia DNT catabolic pathway, perhaps due to direct delivery of oxygen from VHb to this oxygenase [Fish et al, 2001;Lee et al, 2004;Lin et al, 2003].…”

Section: Introductionmentioning

confidence: 90%

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Role of Hemoglobin in Improving Biodegradation of Aromatic Contaminants under Hypoxic Conditions

2008

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Genetic engineering of bacteria using the Vitreoscilla (bacterial) hemoglobin gene has been used to enhance bioremediation of several compounds which are models for, or are themselves, toxic chemicals which may contaminate soil and water. Initial experiments, done mostly in shake flasks, with Escherichia coli, Burkholderia sp. DNT and Pseudomonas aeruginosa demonstrated that expression of Vitreoscilla hemoglobin in heterologous hosts can enhance biodegradation of several aromatic compounds as well as an organophosphorus compound. These studies concentrated for the most part on enhancement of endogenous catabolic capabilities of the hosts; the presence of vgb/VHb enhanced both growth and biodegradation. The initial studies were followed by experiments in systems which more closely approximated conditions that would exist in field applications. These included soil columns, continuous flow reactors and membrane bioreactors. The latter work also enabled calculation of the effects of the presence of vgb/VHb on kinetic parameters such as growth rate, substrate and oxygen utilization rate, and degradation rate of pollutants, etc. Although not always the case, for the most part, and particularly in bioreactors, the advantages due to vgb/VHb were greater under conditions of limited aeration or hypoxic conditions.

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Section: Cometabolism Of 24-dnt By Burkholderia Strains Dnt and Yv1contrasting

confidence: 76%

Section: Cometabolism Of 24-dnt By Burkholderia Strains Dnt and Yv1mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 90%

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Role of Hemoglobin in Improving Biodegradation of Aromatic Contaminants under Hypoxic Conditions

2008

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“…VHb may also provide oxygen to the oxygenases in aromatic catabolic pathways (Lin et al, 2003) and may also be involved in detoxification of NO (Kaur et al, 2002). The Vitreoscilla hemoglobin gene (vgb) has been expressed in a number of microorganisms where it has enhanced their oxygen uptake, and thus aerobic growth and oxygendependent reactions, particularly under hypoxic conditions (Fish et al, 2000;Frey et al, 2000;Patel et al, 2000;Nasr et al, 2001;Urgun-Demirtas et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Enhanced kinetics of genetically engineered Burkholderia cepacia: the role of vgb in the hypoxic metabolism of 2‐CBA

Urgun‐Demirtas

Pagilla

Stark

2004

Biotech & Bioengineering

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Application of Vitreoscilla hemoglobin (VHb) technology to 2-CBA degradation by Burkholderia cepacia strain DNT under hypoxic conditions was studied in continuous culture chemostats. Dechlorination abilities of both recombinant (VHb gene (vgb) containing) and untransformed cells were investigated at various dilution rates to ensure complete degradation of 2-CBA. As the dilution rate increased from 0.025 to 0.25 h(-1), the ratios of chloride release to degraded 2-CBA concentration decreased from 0.95 to 0.72 and from 0.89 to 0.39 for recombinant and untransformed cells, respectively. A nonstoichiometric relationship between chloride release and 2-CBA degradation was more pronounced for untransformed cells. Recombinant cell densities were 0.1-0.2. g L(-1) greater than untransformed cell densities for a range of dilution rates. As the dilution rate increased, the oxygen uptake rate (OUR) and the substrate utilization rate (SUR) decreased for both strains. The OUR/SUR ratio increased as the dilution rate increased for both strains but was much higher for the recombinant strain compared to untransformed cells. The specific 2-CBA degradation rate of recombinant cells was greater than that of untransformed cells (1.17 vs. 0.46 mg CBA (mg) day(-1), and half-saturation constants for recombinant cells were lower than those of untransformed cells (0.18 and 0.32 mg CBA L(-1), respectively). The pseudo-first-order degradation constants, k(1CBA) and k(1ACE), were higher for recombinant cells (6.5 L (mg cells)(-1) day(-1) and 95.6 L (mg cells)(-1) day(-1), respectively) than those of untransformed cells (1.44 L (mg cells)(-1) day(-1) and 73.7 L (mg cells)(-1) day(-1), respectively).

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“…Regen SY), and petunias, overexpressing VHb can enhance the growth and survival of the plant under hypoxia stress (Dordas et al 2003;Mao et al 2003;Li et al 2005). In microbes, attempts have been made to overcome the problem of limiting oxygen by metabolically engineering bacteria to express the vhb transgene under hypoxic conditions (Patel et al 2000;Nasr et al 2001;So et al 2004;Urgun-Demirtas et al 2004). Recently, it was also suggested that VHb can improve tolerance to oxidative, nitrosative, and submergence stresses in host cells, which is based on the integration of new enzymatic functions into the host metabolic network (Kaur et al 2002;Mao et al 2003;Frey et al 2004;Li et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Vitreoscilla Hemoglobin (VHb) Overexpression Increases Hypoxia Tolerance in Zebrafish (Danio rerio)

et al. 2010

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Aquaculture farming may benefit from genetically engineering fish to tolerate environmental stress. Here, we used the vector pCVCG expressing the Vitreoscilla hemoglobin (vhb) gene driven by the common carp β-actin promoter to create stable transgenic zebrafish. The survival rate of the 7-day-old F 2 transgenic fish was significantly greater than that of the sibling controls under 2.5% O 2 (dissolved oxygen (DO), 0.91 mg/l). Meanwhile, we investigated the relative expression levels of several marker genes (hypoxia-inducible factor alpha 1, heat shock cognate 70-kDa protein, erythropoietin, beta and alpha globin genes, lactate dehydrogenase, catalase, superoxide dismutase, and glutathione peroxidase) of transgenic fish and siblings after hypoxia exposure for 156 h. The expression profiles of the vhb transgenic zebrafish revealed that VHb could partially alleviate the hypoxia stress response to improve the survival rate of the fish. These results suggest that that vhb gene may be an efficient candidate for genetically modifying hypoxia tolerance in fish.

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Effects of Culture Conditions on Enhancement of 2,4‐Dinitrotoluene Degradation by BurkholderiaEngineered with the Vitreoscilla Hemoglobin Gene

Cited by 29 publications

References 21 publications

Role of Hemoglobin in Improving Biodegradation of Aromatic Contaminants under Hypoxic Conditions

Role of Hemoglobin in Improving Biodegradation of Aromatic Contaminants under Hypoxic Conditions

Enhanced kinetics of genetically engineered Burkholderia cepacia: the role of vgb in the hypoxic metabolism of 2‐CBA

Vitreoscilla Hemoglobin (VHb) Overexpression Increases Hypoxia Tolerance in Zebrafish (Danio rerio)

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