Effect of Organic Solvents on the Yield of Solvent-Tolerant
            <i>Pseudomonas putida</i>
            S12

Isken, S.; Derks, Antoine; Wolffs, Petra; Bont, J.A.M. de

doi:10.1128/aem.65.6.2631-2635.1999

Cited by 86 publications

(36 citation statements)

References 37 publications

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“…Pseudomonas putida S12 was cultured in chemostats in mineral glucose medium either in the presence or absence of 5 mM toluene. This compound has been used previously as a model to study solvent tolerance in P. putida (Kieboom et al ., 1998a;Isken et al ., 1999;Wery et al ., 2001;Segura et al ., 2005). A concentration of 5 mM toluene is near water saturation and it is well above the threshold that triggers the adaptational responses of P. putida S12 to toluene (Kieboom et al ., 1998b).…”

Section: Resultsmentioning

confidence: 99%

“…Under toluene stress, the biomass yields decreased by 45% and 56% in the N-limited and C-limited medium respectively (Table 1). Previously, Isken and colleagues (Isken et al ., 1999) reported a comparable decrease in cell yield of continuously cultured P. putida S12 in the presence of supersaturating amounts of toluene under C-limited conditions. These observations imply that the energy supply of the cells is severely compromised in the presence of toluene.…”

Section: Resultsmentioning

confidence: 99%

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Chemostat‐based proteomic analysis of toluene‐affected Pseudomonas putida S12

Volkers¹,

Jong²,

Hulst³

et al. 2006

Environmental Microbiology

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The aim of this study was to assess the cellular response of the solvent-tolerant Pseudomonas putida S12 to toluene as the single effector. Proteomic analysis (two-dimensional difference-in-gel-electrophoresis) was used to assess the response of P. putida S12 cultured in chemostats. This approach ensures constant growth conditions, both in the presence and absence of toluene. A considerable negative effect of toluene on the cell yield was found. The need for energy in the defence against toluene was reflected by differentially expressed proteins for cell energy management. In toluene-stressed cells the balance between proton motive force (PMF) enforcing and dissipating systems was shifted. NAD(P)H generating systems were upregulated whereas the major proton-driven system, ATP synthase, was downregulated. Other differentially expressed proteins were identified: outer membrane proteins, transport proteins, stress-related proteins and translation-related proteins. In addition, a protein with no assigned function was found. This study yielded a more detailed view of the effect of toluene on the intracellular energy management of P. putida S12 and several novel leads have been obtained for further targeted investigations.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Chemostat‐based proteomic analysis of toluene‐affected Pseudomonas putida S12

Volkers¹,

Jong²,

Hulst³

et al. 2006

Environmental Microbiology

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“…Estimating the non‐growth‐associated maintenance demand during growth of P. putida S12 in the presence of toluene from the published data of Isken et al . [72] indeed indicates a fivefold increase in energy demand for maintenance. In contrast, cells growing in the presence of BEHP show hardly any increase in maintenance demands and thus potentially have plenty of resources to drive the biocatalytic reaction.…”

Section: Discussionmentioning

confidence: 99%

Metabolic response of Pseudomonas putida during redox biocatalysis in the presence of a second octanol phase

et al. 2008

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A key limitation of whole-cell redox biocatalysis for the production of valuable, specifically functionalized products is substrate/product toxicity, which can potentially be overcome by using solvent-tolerant micro-organisms. To investigate the inter-relationship of solvent tolerance and energy-dependent biocatalysis, we established a model system for biocatalysis in the presence of toxic low logP(ow) solvents: recombinant solvent-tolerant Pseudomonas putida DOT-T1E catalyzing the stereospecific epoxidation of styrene in an aqueous/octanol two-liquid phase reaction medium. Using (13)C tracer based metabolic flux analysis, we investigated the central carbon and energy metabolism and quantified the NAD(P)H regeneration rate in the presence of toxic solvents and during redox biocatalysis, which both drastically increased the energy demands of solvent-tolerant P. putida. According to the driven by demand concept, the NAD(P)H regeneration rate was increased up to eightfold by two mechanisms: (a) an increase in glucose uptake rate without secretion of metabolic side products, and (b) reduced biomass formation. However, in the presence of octanol, only approximately 1% of the maximally observed NAD(P)H regeneration rate could be exploited for styrene epoxidation, of which the rate was more than threefold lower compared with operation with a non-toxic solvent. This points to a high energy and redox cofactor demand for cell maintenance, which limits redox biocatalysis in the presence of octanol. An estimated upper bound for the NAD(P)H regeneration rate available for biocatalysis suggests that cofactor availability does not limit redox biocatalysis under optimized conditions, for example, in the absence of toxic solvent, and illustrates the high metabolic capacity of solvent-tolerant P. putida. This study shows that solvent-tolerant P. putida have the remarkable ability to compensate for high energy demands by boosting their energy metabolism to levels up to an order of magnitude higher than those observed during unlimited growth.

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“…These aromatic hydrocarbons are toxic when they are partitioned into lipid bilayer membranes, leading to significant changes in the structure and functioning of membranes, e.g., the disruption of the membrane potential, the removal of lipids and proteins, and the loss of Mg 2+ and Ca 2+ cations that are vital for membrane integrity. There is considerable interest in the isolation of microbes which are able to thrive on high concentrations of organic solvents and have the potential to eliminate aromatic compounds of low molecular weight [5,6], such as the BTX compounds studied here.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Benzene, Toluene and Xylene byPseudomonas aeruginosa Engineered with theVitreoscilla Hemoglobin Gene

Kahraman¹,

Geçkil²

2005

Eng. Life Sci.

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This study concerns the potential use of Pseudomonas aeruginosa expressing the Vitreoscilla hemoglobin gene for the degradation of important harmful aromatic compounds such as benzene, toluene, and xylene (BTX). The use of these compounds by both strains was determined as the production of cell mass (viable cell number) in a minimal medium containing any one of the BTX compounds as the sole carbon and energy source. Furthermore, the BTX degradation capability of both strains was monitored by measuring the production of 3‐methylcatechol, a common intermediate. For the cells of the logarithmic phase, which were grown at high aeration/high agitation or low aeration/low agitation, the engineered strain showed a better growth rate than the host strain. With the benzene in the medium, the recombinant strain exhibited a higher (up to 4‐fold) cell density than the parental wild‐type strain at this phase. In contrast, regarding the cells of the late stationary phase under high aeration/high agitation conditions, the host strain had generally higher viable cell numbers than the recombinant strain. At this phase this difference was, however, less significant under the conditions of low aeration/low agitation. Similarly, in toluene containing medium (at high aeration/high agitation) the recombinant strain showed a higher cell density which was from a 15‐fold to almost one order of magnitude greater than its parental strain during the logarithmic phase where the cell density of P. aeruginosa remained nearly constant. Contrary to the results with benzene and toluene, both strains exhibited similar growth characteristics when they were grown in the presence of xylene. The positive effect of the oxygen uptake by the recombinant system on the BTX metabolizing activity was also apparent in a high accumulation of 3‐methylcatechol in the cultures of the recombinant strain. At certain points of incubation, the hemoglobin expressing strain showed a significantly (p < 0.05) higher 3‐methylcatechol accumulation than the host strain. These results demonstrated the possible potential of the Vitreoscilla hemoglobin as an efficient oxygen uptake system for the bioremediation of some compounds of environmental concern.

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Effect of Organic Solvents on the Yield of Solvent-Tolerant Pseudomonas putida S12

Cited by 86 publications

References 37 publications

Chemostat‐based proteomic analysis of toluene‐affected Pseudomonas putida S12

Chemostat‐based proteomic analysis of toluene‐affected Pseudomonas putida S12

Metabolic response of Pseudomonas putida during redox biocatalysis in the presence of a second octanol phase

Degradation of Benzene, Toluene and Xylene byPseudomonas aeruginosa Engineered with theVitreoscilla Hemoglobin Gene

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