Loading...

Naphthalene metabolism in Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic microorganism

Zeinali, M ; Sharif University of Technology | 2008

983 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.chemosphere.2008.03.038
  3. Publisher: 2008
  4. Abstract:
  5. The thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, originally isolated in our laboratory from a petroindustrial wastewater contaminated soil in Iran, grows at 50 °C on a broad range of hydrocarbons. Transformation of naphthalene by strain TSH1 which is able to use this two ring-polycyclic aromatic hydrocarbon (PAH) as a sole source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that strain TSH1 initiates its attack on naphthalene by dioxygenation at its C-1 and C-2 positions to give 1,2-dihydro-1,2-dihydroxynaphthalene. The intermediate 2-hydroxycinnamic acid, characteristic of the meta-cleavage of the resulting diol was identified in the acidic extract. Apart from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as an intermediate for the naphthalene pathway of this Nocardia strain. Neither phthalic acid nor salicylic acid metabolites were detected in culture extracts. Enzymatic experiments with cell extract showed the catechol 1,2-dioxygenase activity while transformation of phthalic acid and protocatechuic acid was not observed. The results of enzyme activity assays and identification of benzoic acid in culture extract provide strong indications that further degradation goes through benzoate and β-ketoadipate pathway. Our results indicate that naphthalene degradation by thermophilic N. otitidiscaviarum strain TSH1 differs from the known pathways found for the thermophilic Bacillus thermoleovorans Hamburg 2 and mesophilic bacteria. © 2008 Elsevier Ltd. All rights reserved
  6. Keywords:
  7. Metabolism ; Benzoic acid ; Nocardia ; Thermophile ; Naphthalene ; Carbon ; Catechol 1,2 dioxygenase ; Cell extract ; Coumaric acid ; Hydrocarbon ; Protocatechuic acid ; Salicylic acid ; Metabolites ; Microorganisms ; Bioremediation ; Industrial emission ; isolated population ; Metabolite ; Microbial activity ; Naphthalene ; PAH ; Soil pollution ; Thermophilic bacterium ; Wastewater ; Bacterium identification ; Cell free system ; Degradation ; Enzyme activity ; Mesophile ; Mesophilic bacterium ; Microorganism ; Oxygenation ; Thermophilic archaeon ; Biodegradation, Environmental ; Biotransformation ; Naphthalenes ; Nocardia ; Soil Pollutants ; Temperature ; Water Pollutants, Chemical ; Asia ; Eurasia ; Iran ; Middle East ; Bacteria (microorganisms) ; Geobacillus thermoleovorans ; Nocardia otitidiscaviarum ; Biodegradation
  8. Source: Chemosphere ; Volume 72, Issue 6 , 2008 , Pages 905-909 ; 00456535 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0045653508004086