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Pseudomonas putida

About: Pseudomonas putida is a research topic. Over the lifetime, 6854 publications have been published within this topic receiving 230572 citations.


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TL;DR: The Haldane equation was found to be the most suitable substrate-inhibition model for the specific growth rate of the psychrotrophic bacterium Pseudomonas putida Q5 and the Arrhenius model provided a better prediction of the temperature dependence of K(S).
Abstract: The temperature-dependent performance of mixed-culture wastewater treatment processes may be strongly influenced by their content of psychrotrophic bacteria. In this work, the effect of temperature on cell growth and phenol biodegradation kinetics of the psychrotrophic bacterium Pseudomonas putida Q5 were determined using both batch and continuous cultures in the range of 10-25 degrees C. The Haldane equation was found to be the most suitable substrate-inhibition model for the specific growth rate. The Haldane parameters mu(max) and K(I) were best modeled by a square-root dependency on temperature. However, the Arrhenius model provided a better prediction of the temperature dependence of K(S). The variation of the yield constant with temperature also was studied experimentally. Comparisons with results of previous workers are presented.

80 citations

Journal ArticleDOI
TL;DR: The P-3 and P-4 media were used as selective media for P. fluorescens and a small proportion of those of P. putida produced fluorescent pigment on the P-1 or P-2 medium unlike the others, suggesting that the medium can be used as a selective medium for P- putida strains.
Abstract: Four selective media for Pseudomonas strains producing fluorescent pigment (P-l medium), Pseudomonas putida strains (P-2 medum) and Pseudomonas fluorescens strains (P-3 and P-4 media) were proposed on the basis of the assimilation of carbon sources by the strains. One hundred and three strains of Pseudomonas species producing fluorescent pigment were isolated from soils and plant roots, and used for the evaluation of these selective media. Most of the strains identified as P. putida produced fluorescent pigment on P-2 medium unlike the others, suggesting that the medium can be used as a selective medium for P. putida strains. Most of the strains of P. fluorescens and a small proportion of those of P. putida produced fluorescent pigment on the P-3 or P-4 medium. As the number of P. putida which produced fluorescent pigment on the P-3 and P-4 media was far smaller than the number of P. fluorescens on P-3 and P-4 media, the P-3 and P-4 media were used as selective media for P. fluorescens. The distribution o...

80 citations

Journal ArticleDOI
TL;DR: Differences in the abilities of the CF-oxidizing strains to degrade other halogenated compounds were also identified, including toluene 4-monooxygenase genes from P. mendocina KRMT, which contains a tmo mutation.
Abstract: Seven toluene-oxidizing bacterial strains (Pseudomonas mendocina KR1, Burkholderia cepacia G4, Pseudomonas putida F1, Pseudomonas pickettii PKO1, and Pseudomonas sp. strains ENVPC5, ENVBF1, and ENV113) were tested for their ability to degrade chloroform (CF). The greatest rate of CF oxidation was achieved with strain ENVBF1 (1.9 nmol/min/mg of cell protein). CF also was oxidized by P. mendocina KR1 (0.48 nmol/min/mg of cell protein), strain ENVPC5 (0.49 nmol/min/mg of cell protein), and Escherichia coli DH510B(pRS202), which contained cloned toluene 4-monooxygenase genes from P. mendocina KR1 (0.16 nmol/min/mg of cell protein). Degradation of [14C]CF and ion analysis of culture extracts revealed that CF was mineralized to CO2 (approximately 30 to 57% of the total products), soluble metabolites (approximately 15%), a total carbon fraction irreversibly bound to particulate cellular constituents (approximately 30%), and chloride ions (approximately 75% of the expected yield). CF oxidation by each strain was inhibited in the presence of trichloroethylene, and acetylene significantly inhibited trichloroethylene oxidation by P. mendocina KR1. Differences in the abilities of the CF-oxidizing strains to degrade other halogenated compounds were also identified. CF was not degraded by B. cepacia G4, P. putida F1, P. pickettii PKO1, Pseudomonas sp. strain ENV113, or P. mendocina KRMT, which contains a tmo mutation.

80 citations

Journal ArticleDOI
P Cerdan1, Alain Wasserfallen1, M Rekik1, K. N. Timmis1, Shigeaki Harayama1 
TL;DR: The wild-type catechol 2,3-dioxygenase was inactivated during the catalysis of 4-ethylcatechol and thus had a low partition ratio for this substrate, whereas the two mutant enzymes, 4 ECR1 and 4ECR6, had higher partition ratios for it.
Abstract: Catechol 2,3-dioxygenase encoded by TOL plasmid pWW0 of Pseudomonas putida consists of four identical subunits, each containing one ferrous ion. The enzyme catalyzes ring cleavage of catechol, 3-methylcatechol, and 4-methylcatechol but shows only weak activity toward 4-ethylcatechol. Two mutants of catechol 2,3-dioxygenases (4ECR1 and 4ECR6) able to oxidize 4-ethylcatechol, one mutant (3MCS) which exhibits only weak activity toward 3-methylcatechol but retained the ability to cleave catechol and 4-methylcatechol, and one phenotypic revertant of 3MCS (3MCR) which had regained the ability to oxidize 3-methylcatechol were characterized by determining their Km and partition ratio (the ratio of productive catalysis to suicide catalysis). The amino acid substitutions in the four mutant enzymes were also identified by sequencing their structural genes. Wild-type catechol 2,3-dioxygenase was inactivated during the catalysis of 4-ethylcatechol and thus had a low partition ratio for this substrate, whereas the two mutant enzymes, 4ECR1 and 4ECR6, had higher partition ratios for it. Similarly, mutant enzyme 3MCS had a lower partition ratio for 3-methylcatechol than that of 3MCR. Molecular oxygen was required for the inactivation of the wild-type enzyme by 4-ethylcatechol and of 3MCS by 3-methylcatechol, and the inactivated enzymes could be reactivated by incubation with FeSO4 plus ascorbic acid. The enzyme inactivation is thus most likely mechanism based and occurred principally by oxidation and/or removal of the ferrous ion in the catalytic center. In general, partition ratios for catechols lower than 18,000 did not support bacterial growth. A possible meaning of the critical value of the partition ratio is discussed.

80 citations

Journal ArticleDOI
TL;DR: New bioplastics containing aromatic or mixtures of aliphatic and aromatic monomers have been obtained using genetically engineered strains of Pseudomonas putida, and using one of these polyesters, the authors obtained polymeric microspheres that could be used as drug vehicles.
Abstract: New bioplastics containing aromatic or mixtures of aliphatic and aromatic monomers have been obtained using genetically engineered strains of Pseudomonas putida. The mutation (-) or deletion (Delta) of some of the genes involved in the beta-oxidation pathway (fadA(-), fadB(-) Delta fadA or Delta fad BA mutants) elicits a strong intracellular accumulation of unusual homo- or co-polymers that dramatically alter the morphology of these bacteria, as more than 90% of the cytoplasm is occupied by these macromolecules. The introduction of a blockade in the beta-oxidation pathway, or in other related catabolic routes, has allowed the synthesis of polymers other than those accumulated in the wild type (with regard to both monomer size and relative percentage), the accumulation of certain intermediates that are rapidly catabolized in the wild type and the accumulation in the culture broths of end catabolites that, as in the case of phenylacetic acid, phenylbutyric acid, trans-cinnamic acid or their derivatives, have important medical or pharmaceutical applications (antitumoral, analgesic, radiopotentiators, chemopreventive or antihelmintic). Furthermore, using one of these polyesters (poly 3-hydroxy-6-phenylhexanoate), we obtained polymeric microspheres that could be used as drug vehicles.

80 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023184
2022345
2021182
2020246
2019226
2018206