BIOCAT - biocatalytic process for the "green" production of value-added fluoroaromatic comppounds

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Chryseobacterium palustre sp. nov. and Chryseobacterium humi sp. nov., isolated from industrially contaminated sediments

Publication . Pires, Carlos; Carvalho, Maria F.; Marco, Paolo De; Magan, Naresh; Castro, Paula M. L.

Two Gram-staining-negative bacterial strains, designated 3A10T and ECP37T, were isolated from sediment samples collected from an industrially contaminated site in northern Portugal. These two organisms were rod-shaped, non-motile, aerobic, catalase- and oxidase-positive and formed yellow colonies. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 1{omega}9c and iso-C17 : 0 3-OH. The G+C content of the DNA of strains 3A10T and ECP37T was 43 and 34 mol%, respectively. The major isoprenoid quinone of the two strains was MK-6. 16S rRNA gene sequence analysis revealed that strains 3A10T and ECP37T were members of the family Flavobacteriaceae and were related phylogenetically to the genus Chryseobacterium. Strain 3A10T showed 16S rRNA gene sequence similarity values of 97.2 and 96.6 % to the type strains of Chryseobacterium antarcticum and Chryseobacterium jeonii, respectively; strain ECP37T showed 97.3 % similarity to the type strain of Chryseobacterium marinum. DNA–DNA hybridization experiments revealed levels of genomic relatedness of <70 % between strains 3A10T and ECP37T and between these two strains and the type strains of C. marinum, C. antarcticum and C. jeonii, justifying their classification as representing two novel species of the genus Chryseobacterium. The names proposed for these organisms are Chryseobacterium palustre sp. nov. (type strain 3A10T =LMG 24685T =NBRC 104928T) and Chryseobacterium humi sp. nov. (type strain ECP37T =LMG 24684T =NBRC 104927T).

2010Journal article

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Isolation and characterization of a Rhodococcus strain able to degrade 2-fluorophenol

Publication . Duque, Anouk F.; Hasan, Syed A.; Bessa, Vânia S.; Carvalho, Maria F.; Samin, Ghufrana; Janssen, Dick B.; Castro, Paula M. L.

A pure bacterial culture able to utilize 2- fluorophenol (2-FP) as sole carbon and energy source was isolated by selective enrichment from sediments collected from a contaminated site in Northern Portugal. 16S rRNA gene analysis showed that the organism (strain FP1) belongs to the genus Rhodococcus. When grown aerobically on 2-FP, growth kinetics of strain FP1 followed the Luong model. An inhibitory effect of increasing 2-FP concentrations was observed with no growth occurring at 2- FP levels higher than ca. 4 mM. Rhodococcus strain FP1 was able to degrade a range of other organofluorine compounds, including 2-fluorobenzoate, 3-fluorobenzoate, 4-fluorobenzoate, 3-fluorophenol, 4-fluorophenol, 3-fluorocatechol, and 4-fluorocatechol, as well as chlorinated compounds such as 2-chlorophenol and 4-chlorophenol. Experiments with cell-free extracts and partially purified enzymes indicated that the first step of 2-fluorophenol metabolism was conversion to 3-fluorocatechol, suggesting an unusual pathway for fluoroaromatic metabolism. To our knowledge, this is the first time that utilization of 2-FP as a growth substrate by a pure bacterial culture is reported.

2012Journal article

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Degradation of difluorobenzenes by the wild strain Labrys portucalensis

Publication . Moreira, Irina S.; Amorim, Catarina L.; Carvalho, Maria F.; Castro, Paula M. L.

This study focuses on the biodegradation of difluorobenzenes (DFBs), compounds commonly used as intermediates in the industrial synthesis of various pharmaceutical and agricultural chemicals. A previously isolated microbial strain (strain F11), identified as Labrys portucalensis, able to degrade fluorobenzene (FB) as sole carbon and energy source, was tested for its capability to degrade 1,2-, 1,3- and 1,4-DFB in batch cultures. Strain F11 could use 1,3-DFB as a sole carbon and energy source, with quantitative release of fluoride, but 1,4-DFB was only degraded and defluorinated when FB was supplied simultaneously. Growth of strain F11 with 0.5 mM of 1,3-DFB led to stoichiometric release of fluoride ion. The same result was obtained in cultures fed with 1 mM of 1,3-DFB or 0.5 mM of 1,4-DFB, in the presence of 1 mM of FB. No growth occurred with 1,2-DFB as substrate, and degradation of FB was inhibited when supplied simultaneously with 1,2-DFB. To our knowledge, this is the first time biodegradation of 1,3-DFB as a sole carbon and energy source, and cometabolic degradation of 1,4- DFB, by a single bacterium, is reported.

2012Journal article

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