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Degradation of 4-n-nonylphenol under nitrate reducing conditions.

De Weert JP, Viñas M, Grotenhuis T, Rijnaarts HH, Langenhoff AA - Biodegradation (2010)

Bottom Line: Biodegradation of NP can reduce its toxicological risk.The largest change in diversity was observed between the enrichments of the third and fourth generation, and further enrichment did not affect the diversity.Phenol was degraded in all cases, but did not affect the linear NP degradation under denitrifying conditions and did not initiate the degradation of tNP and linear NP under the other tested conditions.

View Article: PubMed Central - PubMed

Affiliation: Deltares, Utrecht, The Netherlands. jasperien.deweert@deltares.nl

ABSTRACT
Nonylphenol (NP) is an endocrine disruptor present as a pollutant in river sediment. Biodegradation of NP can reduce its toxicological risk. As sediments are mainly anaerobic, degradation of linear (4-n-NP) and branched nonylphenol (tNP) was studied under methanogenic, sulphate reducing and denitrifying conditions in NP polluted river sediment. Anaerobic bioconversion was observed only for linear NP under denitrifying conditions. The microbial population involved herein was further studied by enrichment and molecular characterization. The largest change in diversity was observed between the enrichments of the third and fourth generation, and further enrichment did not affect the diversity. This implies that different microorganisms are involved in the degradation of 4-n-NP in the sediment. The major degrading bacteria were most closely related to denitrifying hexadecane degraders and linear alkyl benzene sulphonate (LAS) degraders. The molecular structures of alkanes and LAS are similar to the linear chain of 4-n-NP, this might indicate that the biodegradation of linear NP under denitrifying conditions starts at the nonyl chain. Initiation of anaerobic NP degradation was further tested using phenol as a structure analogue. Phenol was chosen instead of an aliphatic analogue, because phenol is the common structure present in all NP isomers while the structure of the aliphatic chain differs per isomer. Phenol was degraded in all cases, but did not affect the linear NP degradation under denitrifying conditions and did not initiate the degradation of tNP and linear NP under the other tested conditions.

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Overview of enrichments, dilution series, DNA samples and clone library sample of batches originating with 4-n-NP (NP) and with 4-n-NP and phenol (NP + P)
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Fig2: Overview of enrichments, dilution series, DNA samples and clone library sample of batches originating with 4-n-NP (NP) and with 4-n-NP and phenol (NP + P)

Mentions: Second to fifth generation enrichments were made of the 4-n-NP degrading batches with nitrate reducing medium. Branched NP was not added since degradation of tNP was not observed. Phenol was not added for further enrichment. The enrichments originating from the first generation enrichment with 4-n-NP were encoded as “NP” and the enrichments originating from the first generation enrichment with 4-n-NP plus phenol were encoded as “NP + P”. Besides transfers also dilutions series were performed to further enrich the 4-n-NP degrading population. An overview of the enrichments and dilution series is shown in Fig. 2.Fig. 2


Degradation of 4-n-nonylphenol under nitrate reducing conditions.

De Weert JP, Viñas M, Grotenhuis T, Rijnaarts HH, Langenhoff AA - Biodegradation (2010)

Overview of enrichments, dilution series, DNA samples and clone library sample of batches originating with 4-n-NP (NP) and with 4-n-NP and phenol (NP + P)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3008940&req=5

Fig2: Overview of enrichments, dilution series, DNA samples and clone library sample of batches originating with 4-n-NP (NP) and with 4-n-NP and phenol (NP + P)
Mentions: Second to fifth generation enrichments were made of the 4-n-NP degrading batches with nitrate reducing medium. Branched NP was not added since degradation of tNP was not observed. Phenol was not added for further enrichment. The enrichments originating from the first generation enrichment with 4-n-NP were encoded as “NP” and the enrichments originating from the first generation enrichment with 4-n-NP plus phenol were encoded as “NP + P”. Besides transfers also dilutions series were performed to further enrich the 4-n-NP degrading population. An overview of the enrichments and dilution series is shown in Fig. 2.Fig. 2

Bottom Line: Biodegradation of NP can reduce its toxicological risk.The largest change in diversity was observed between the enrichments of the third and fourth generation, and further enrichment did not affect the diversity.Phenol was degraded in all cases, but did not affect the linear NP degradation under denitrifying conditions and did not initiate the degradation of tNP and linear NP under the other tested conditions.

View Article: PubMed Central - PubMed

Affiliation: Deltares, Utrecht, The Netherlands. jasperien.deweert@deltares.nl

ABSTRACT
Nonylphenol (NP) is an endocrine disruptor present as a pollutant in river sediment. Biodegradation of NP can reduce its toxicological risk. As sediments are mainly anaerobic, degradation of linear (4-n-NP) and branched nonylphenol (tNP) was studied under methanogenic, sulphate reducing and denitrifying conditions in NP polluted river sediment. Anaerobic bioconversion was observed only for linear NP under denitrifying conditions. The microbial population involved herein was further studied by enrichment and molecular characterization. The largest change in diversity was observed between the enrichments of the third and fourth generation, and further enrichment did not affect the diversity. This implies that different microorganisms are involved in the degradation of 4-n-NP in the sediment. The major degrading bacteria were most closely related to denitrifying hexadecane degraders and linear alkyl benzene sulphonate (LAS) degraders. The molecular structures of alkanes and LAS are similar to the linear chain of 4-n-NP, this might indicate that the biodegradation of linear NP under denitrifying conditions starts at the nonyl chain. Initiation of anaerobic NP degradation was further tested using phenol as a structure analogue. Phenol was chosen instead of an aliphatic analogue, because phenol is the common structure present in all NP isomers while the structure of the aliphatic chain differs per isomer. Phenol was degraded in all cases, but did not affect the linear NP degradation under denitrifying conditions and did not initiate the degradation of tNP and linear NP under the other tested conditions.

Show MeSH