Aromatic sulfonates (R-SO3-) can be used as sulfur sources by sulfate-starved bacteria in laboratory cultures and the corresponding phenols are excreted from the cells. The present study was conducted to demonstrate whether such desulfonation reactions also occur in sulfate-leached agricultural soil, where desulfonation of organic sulfur compounds may have agronomic importance as a S source for plants. Xenobiotic linear alkylbenzene sulfonates (LAS) were added to nominal concentrations of 0, 10 and 100 mg kg(-1) dry weight in a sandy soil that was depleted in sulfate by leaching the soil with water (sulfate depletion, similar to75%). The soil was incubated at 20 degreesC in duplicate 3-dm(3) mesocosms for 8 weeks. Primary degradation of LAS was rapid with half-lives of 1-4 days. Sulfophenylcarboxylates were identified and quantified as intermediates, whereas linear alkylphenols (the expected primary desulfonation products) were not detected by high-pressure liquid chromatography coupled with both fluorescence and electrospray ionization-mass spectrometry. Thus, LAS was used by the bacteria as a source of energy and carbon, rather than as a source of sulfur. Measurements of soil pH, fluorescein diacetate (FDA) hydrolysis and arylsulfatase activity showed that stable microbial conditions prevailed in the soil mesocosms. FDA hydrolysis (a measure of total microbial activity) was transiently inhibited at the highest LAS concentrations. Arylsulfatase activity (i.e., hydrolysis of aromatic sulfate esters) was not significantly affected by the soil incubation, although arylsulfatases may be upregulated in sulfate-starved bacteria. However, an increased production of arylsulfatase may be difficult to detect due to the background of extracellular arylsulfatases stabilised in the soil. Therefore, the present data does not exclude a regulatory response to sulfate depletion by the soil microorganisms. However, the importance of desulfonation reactions in natural environments still needs to be demonstrated.

Biodegradation of linear alkylbenzene sulfonates in sulfate-leached soil mesocosms

POJANA, Giulio;MARCOMINI, Antonio
2003

Abstract

Aromatic sulfonates (R-SO3-) can be used as sulfur sources by sulfate-starved bacteria in laboratory cultures and the corresponding phenols are excreted from the cells. The present study was conducted to demonstrate whether such desulfonation reactions also occur in sulfate-leached agricultural soil, where desulfonation of organic sulfur compounds may have agronomic importance as a S source for plants. Xenobiotic linear alkylbenzene sulfonates (LAS) were added to nominal concentrations of 0, 10 and 100 mg kg(-1) dry weight in a sandy soil that was depleted in sulfate by leaching the soil with water (sulfate depletion, similar to75%). The soil was incubated at 20 degreesC in duplicate 3-dm(3) mesocosms for 8 weeks. Primary degradation of LAS was rapid with half-lives of 1-4 days. Sulfophenylcarboxylates were identified and quantified as intermediates, whereas linear alkylphenols (the expected primary desulfonation products) were not detected by high-pressure liquid chromatography coupled with both fluorescence and electrospray ionization-mass spectrometry. Thus, LAS was used by the bacteria as a source of energy and carbon, rather than as a source of sulfur. Measurements of soil pH, fluorescein diacetate (FDA) hydrolysis and arylsulfatase activity showed that stable microbial conditions prevailed in the soil mesocosms. FDA hydrolysis (a measure of total microbial activity) was transiently inhibited at the highest LAS concentrations. Arylsulfatase activity (i.e., hydrolysis of aromatic sulfate esters) was not significantly affected by the soil incubation, although arylsulfatases may be upregulated in sulfate-starved bacteria. However, an increased production of arylsulfatase may be difficult to detect due to the background of extracellular arylsulfatases stabilised in the soil. Therefore, the present data does not exclude a regulatory response to sulfate depletion by the soil microorganisms. However, the importance of desulfonation reactions in natural environments still needs to be demonstrated.
File in questo prodotto:
File Dimensione Formato  
2003_Elsgaard et al.Chemosphere-Biodegradation.pdf

non disponibili

Tipologia: Documento in Post-print
Licenza: Accesso chiuso-personale
Dimensione 144.01 kB
Formato Adobe PDF
144.01 kB Adobe PDF   Visualizza/Apri

I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/15486
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 13
social impact