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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: Results indicate that the isopropylbenzene degradation pathway encoded by linear plasmid pBD2 is initiated by an isopopylbenZene dioxygenase analogous to toluene dionygenase, as well as the arsenite resistance and mercury resistance phenotypes.
Abstract: Rhodococcus erythropolis BD2, which is able to utilize isopropylbenzene as a sole carbon and energy source, was shown to contain a conjugative linear plasmid, pBD2. The estimated size of pBD2 is 208 to 212 kb. Linear plasmid-deficient strains had lost both the isopropylbenzene degradation and trichloroethene degradation characteristics, as well as the arsenite resistance and mercury resistance phenotypes. Reintroduction of pBD2 restored all four characteristics. Conjugational transfer of pBD2 to a plasmidless mutant of strain BD2 and other R. erythropolis strains occurred at frequencies between 3.5 x 10(-5) and 2.6 x 10(-3) transconjugants per recipient. R. erythropolis BD2 degrades isopropylbenzene via 3-isopropylcatechol and 2-hydroxy-6-oxo-7-methylocta-2,4-dienoate. Both isopropylbenzene-oxidizing and meta-cleavage activities were shown to correspond with the presence of pBD2. Southern hybridizations with DNA encoding the toluene dioxygenase structural genes (todC1C2BA) from Pseudomonas putida F1 revealed homology to linear plasmid DNA. These results indicate that the isopropylbenzene degradation pathway encoded by linear plasmid pBD2 is initiated by an isopropylbenzene dioxygenase analogous to toluene dioxygenase. Images
92 citations
TL;DR: d-xylonic acid is a versatile platform chemical with reported applications as complexing agent or chelator, in dispersal of concrete, and as a precursor for compounds such as co-polyamides, polyesters, hydrogels and 1,2,4-butanetriol.
Abstract: d-Xylonic acid is a versatile platform chemical with reported applications as complexing agent or chelator, in dispersal of concrete, and as a precursor for compounds such as co-polyamides, polyesters, hydrogels and 1,2,4-butanetriol. With increasing glucose prices, d-xylonic acid may provide a cheap, non-food derived alternative for gluconic acid, which is widely used (about 80 kton/year) in pharmaceuticals, food products, solvents, adhesives, dyes, paints and polishes. Large-scale production has not been developed, reflecting the current limited market for d-xylonate. d-Xylonic acid occurs naturally, being formed in the first step of oxidative metabolism of d-xylose by some archaea and bacteria via the action of d-xylose or d-glucose dehydrogenases. High extracellular concentrations of d-xylonate have been reported for various bacteria, in particular Gluconobacter oxydans and Pseudomonas putida. High yields of d-xylonate from d-xylose make G. oxydans an attractive choice for biotechnical production. G. oxydans is able to produce d-xylonate directly from plant biomass hydrolysates, but rates and yields are reduced because of sensitivity to hydrolysate inhibitors. Recently, d-xylonate has been produced by the genetically modified bacterium Escherichia coli and yeast Saccharomyces cerevisiae and Kluyveromyces lactis. Expression of NAD+-dependent d-xylose dehydrogenase of Caulobacter crescentus in either E. coli or in a robust, hydrolysate-tolerant, industrial Saccharomyces cerevisiae strain has resulted in d-xylonate titres, which are comparable to those seen with G. oxydans, at a volumetric rate approximately 30 % of that observed with G. oxydans. With further development, genetically modified microbes may soon provide an alternative for production of d-xylonate at industrial scale.
92 citations
TL;DR: The carbon mass balance study confirmed that benzene and toluene were completely mineralized to CO2 and H2O without producing any identifiable intermediate metabolites.
Abstract: Pseudomonas putida and Pseudomonas fluorescens present as a coculture were studied for their abilities to degrade benzene, toluene, ethylbenzene, and xylenes (collectively known as BTEX) under various growth conditions. The coculture effectively degraded various concentrations of BTEX as sole carbon sources. However, all BTEX compounds showed substrate inhibition to the bacteria, in terms of specific growth, degradation rate, and cell net yield. Cell growth was completely inhibited at 500mgl−1 of benzene, 600mgl−1 of o-xylene, and 1000mgl−1 of toluene. Without aeration, aerobic biodegradation of BTEX required additional oxygen provided as hydrogen peroxide in the medium. Under hypoxic conditions, however, nitrate could be used as an alternative electron acceptor for BTEX biodegradation when oxygen was limited and denitrification took place in the culture. The carbon mass balance study confirmed that benzene and toluene were completely mineralized to CO2 and H2O without producing any identifiable intermediate metabolites.
92 citations
TL;DR: Two proteins, encoded on TOL plasmid pWW0 of Pseudomonas putida and that encoded on the chromosome of Acinetobacter calcoaceticus, were sequenced and suggest two amino acids, lysine and tyrosine, as catalytically important residues.
Abstract: In the aerobic degradation of benzoate by bacteria, benzoate is first dihydroxylated by a ring-hydroxylating dioxygenase to form a cis-diol (1,2-dihydroxycyclohexa-3,4-diene carboxylate) which is subsequently transformed to a catechol by an NAD(+)-dependent cis-diol dehydrogenase. The structural gene for this dehydrogenase, encoded on TOL plasmid pWW0 of Pseudomonas putida (xylL) and that encoded on the chromosome of Acinetobacter calcoaceticus (benD), were sequenced. They encode polypeptides of about 28 kDa in size. These proteins are similar to each other, exhibiting 58% sequence identity. They are also similar to other proteins of at least 20 different functions, which are members of the short-chain alcohol dehydrogenase family. The alignment of these proteins suggest two amino acids, lysine and tyrosine, as catalytically important residues.
92 citations
TL;DR: Results support the following conclusions: (i) the n-alkane growth specificity of P. putida PpG6 is due to the substrate specificity of whole-cell alkane hydroxylation; (ii) there is a single alkane Hydroxylase enzyme complex; (iii) the physiological role of this complex is to initiate the monoterminal oxidation of alkane chains.
Abstract: Pseudomonas putida PpG6 is able to utilize purified n-alkanes of six to ten carbon atoms for growth. It can also grow on the primary terminal oxidation products of these alkanes and on 1-dodecanol but not on the corresponding 2-ketones or 1,6-hexanediol, adipic acid, or pimelic acid. Revertible point mutants can be isolated which have simultaneously lost the ability to grow on all five n-alkane growth substrates but which can still grow on octanol or nonanol. An acetate-negative mutant defective in isocitrate lysase activity is unable to grow on even-numbered alkanes and fatty acids. Analysis of double mutants defective in acetate and propionate or in acetate and glutarate metabolism shows that alkane carbon is assimilated only via acetyl-coenzyme A and propionyl-coenzyme A. These results support the following conclusions: (i) The n-alkane growth specificity of P. putida PpG6 is due to the substrate specificity of whole-cell alkane hydroxylation; (ii) there is a single alkane hydroxylase enzyme complex; (iii) the physiological role of this complex is to initiate the monoterminal oxidation of alkane chains; and (iv) straight-chain fatty acids from butyric through nonanoic are degraded exclusively by beta-oxidation from the carboxyl end of the molecule.
92 citations