Modeling growth kinetics and carbazole degradation kinetics of a Pseudomonas aeruginosa strain isolated from refinery sludge and uptake considerations during growth on carbazole.
Sci Total Environ
; 738: 140277, 2020 Oct 10.
Article
en En
| MEDLINE
| ID: mdl-32806351
Although bacterial degradation of polynuclear aromatic hydrocarbons (PAH) have been studied using various pure cultures, only a few studies have explored the degradation kinetics and uptake mechanism of nitrogen heterocyclic PAHs (PANH) with three or more rings. This work explored growth kinetics of a PAH degrading bacterial strain, Pseudomonas aeruginosa RS1 on carbazole (CBZ) and concomitant degradation kinetics of CBZ over the concentration range 25 to 500 mg/L. For CBZ acclimatized strain, the specific growth rate (µ) and specific CBZ uptake rate (q) varied from 0.96 ± 0.05 to 2 ± 0.15 day-1 and from 0.002 ± 0.001 to 0.02 ± 0.01 mg CBZ mg VSS-1 day-1, respectively. The Moser and Monod model provided best fits to the µ vs CBZ concentration and q vs CBZ concentration profiles, respectively. Biosurfactant activity did not play a role in CBZ uptake. However, elevation in cell surface hydrophobicity as revealed through the water contact angle values on bacterial cell mat indicated the possible role of direct interfacial uptake in facilitating CBZ uptake over and above uptake after dissolution. Elevated catechol 1,2-dioxygenase enzyme activity was observed during CBZ degradation. Interestingly, the specific activity of this enzyme was higher in the culture supernatant than in the cell extract. However, during CBZ degradation, accumulation of some toxic metabolites in the aqueous phase was revealed through increase in TOC of the aqueous phase and Kirby-Bauer disc diffusion study performed using a E. coli strain. Both aqueous phase TOC and toxicity decreased beyond the log growth phase indicating further utilization of the degradation intermediates.
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Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pseudomonas aeruginosa
/
Aguas del Alcantarillado
Idioma:
En
Revista:
Sci Total Environ
Año:
2020
Tipo del documento:
Article
País de afiliación:
India
Pais de publicación:
Países Bajos