Optimization of media composition for enhancing carbazole degradation by Pseudomonas aeruginosa RS1 (original) (raw)
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Properties, environmental fate and biodegradation of carbazole
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The last two decades had witnessed extensive investigation on bacterial degradation of carbazole, an N-heterocyclic aromatic hydrocarbon. Specifically, previous studies have reported the primary importance of angular dioxygenation, a novel type of oxygenation reaction, which facilitates mineralization of carbazole to intermediates of the TCA cycle. Proteobacteria and Actinobacteria are the predominant bacterial phyla implicated in this novel mode of dioxygenation, while anthranilic acid and catechol are the signature metabolites. Several studies have elucidated the degradative genes involved, the diversity of the car gene clusters and the unique organization of the car gene clusters in marine carbazole degraders. However, there is paucity of information regarding the environmental fate as well as industrial and medical importance of carbazole and its derivatives. In this review, attempt is made to harness this information to present a comprehensive outlook that not only focuses on c...
Carbazole degradation in the soil microcosm by tropical bacterial strains
Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 2015
In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g) after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized) soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg), 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg-1 h-1. The combination of the three isolates as ...
STUDY OF CARBAZOLE DEGRADING MARINE AND TERRESTRIAL BACTERIAL ISOLATES FROM VALSAD DISTRICT
Journal of innovative technology and emerging research, 2019
Carbazole is a nitrogen heterocyclic compound released into the environment, used as a chemical feed stock for the production of dyes, medicines and plastics. Carbazole and their derivatives are detected in atmospheric samples, river sediments, marine water and ground water. Enriched Mineral salts medium (MSM) broth was used to isolate bacteria able to use carbazole as a sole Carbon and Nitrogen and plate assay using MSM agar plate was developed to select carbazole degrading microorganisms. Ten different bacterial isolates were obtained which were capable of utilizing carbazole as the only sole source of carbon and nitrogen added. From the obtained ten isolates C:1, C:2 and C: 3 were from marine water samples, C:4, C:5 and C:6 from marine soil samples, C:7 and C:8 from Pond water samples and C:9, C:10 were from garage soil samples. All isolates were further studied for their "Bioavailability assay" by using different stress and favourable conditions, among all C: 2 isolate showed the maximum considerable and noticeable result in MSM medium. From the bioavailability assay results carbazole degradation studies was carried out using C: 2 isolate by adding 100 ppm and 500 ppm concentration of carbazole in MSM broth medium from which the concentration of carbazole reduced to 8.33 ppm and 50 ppm in 144 hours containing 100 ppm and 500 ppm respectively. Immobilization studies were carried by immobilizing C: 2 isolate in the form of calcium-alginate beads and PVA-alginate beads. Study of Mechanical stability of calcium-alginate and PVA-alginate beads was checked by sonication. PVA-alginate beads were more stable than calcium-alginate beads. Viability of the immobilized cells was tested by calculating colony forming units using both the types of beads, PVA-alginate beads shows more viability than calcium-alginate beads. Carbazole degradation studies with immobilized cells was done by taking absorbance OD600, the concentration reduced to 41.66 ppm and 33.33 ppm in 144 hours using Calcium-alginate beads and PVA-alginate beads respectively containing 100 ppm concentration of carbazole and 241.6 ppm and 120.8 ppm respectively containing 500 ppm concentration of carbazole.
Brazilian Archives of Biology and Technology, 2005
In this work, the 1082bp PCR product corresponding to carBaBb genes that encode the heterotetrameric enzyme 2'-aminobiphenyl-2,3-diol 1,2-dioxygenase (CarB), involved in the Pseudomonas stutzeri ATCC 31258 carbazole degradation pathway, was cloned using the site-specific recombination system. Recombinant clones were confirmed by PCR, restriction enzyme digestion and sequencing. CarB dioxygenase was expressed in high levels and in active form in Escherichia coli BL21-SI using the His-tagged expression vector pDEST TM17 and salt induction for 4h.