Thesis

The toxicity of o-cresol and 2,4-dimethylphenol on anaerobic microbial associations

Downloadable Content

Download PDF
Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2014
Thesis identifier
  • T13726
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • The study of anaerobic bacterial growth associations plays an important role in the analysis of the toxicity and effect of pollutants. These associations can be found in the environment, for example in groundwater or wastewater treatment plants or even in the gut of animals. The aims of this study were to compare the toxicity exhibited on anaerobic growth associations by two similar alkylphenolic compounds, o-cresol and 2,4-dimethylphenol (DMP), individually and combined, and examine the specific effect these compounds had on individual bacterial groups within the consortium. Through the use of anaerobic batch cultures, the inhibitory concentrations and effects of o-cresol and 2,4-dimethylphenol on anaerobic processes were analysed. Concentrations of o-cresol ≥ 1.85mM were shown to have an inhibitory effect on sulphate reduction, acetogenesis and methanogenesis. At concentrations ≥ 7.4mM complete inhibition of sulphate reduction was noted and the acetogenic and methanogenic processes were greatly reduced, concentrations ≥ 9.3mM appear to cause complete inhibition of methane production. 2,4-dimethylphenol inhibited bacterial groups at concentrations ≥ 0.41mM; complete inhibition of sulphate production was observed at concentrations of DMP ≥3.28mM. Although methane production was significantly reduced at the highest concentration (4.1mM) complete inhibition was not observed. It was found that DMP was more toxic to all the bacteria and archaea within the consortium than o-cresol. Use of continuous flow systems allowed for the separation of the microbial groups within the consortium allowing for the analysis of the direct effect of o-cresol and 2,4- Dimethylphenol. Analysis of the results indicated that the compounds inhibited all the microbial groups, although with varying x degrees of success. It was observed that acetoclastic methanogenic bacteria are more resilient to the toxic effect of the compounds than hydrogenotrophic methanogens and sulphate reducing bacteria. The combined toxicity of these compounds was analysed utilising batch cultures. The combined toxic effect on the growth consortium was observed after addition of both of these compounds to batch cultures. The results showed that, when combined, these compounds exhibited a toxic effect on the consortium, which was synergistic in nature. This study has highlighted the toxic effects of o-cresol and DMP on anaerobic consortia and the importance of the synotrophic relationships between the different bacterial and archaeal groups. It is important that work in this field is carried on to develop a better understanding of the implications of toxic chemical spills and their impact on the groundwater environment.
Resource Type
DOI
Date Created
  • 2014
Former identifier
  • 1032443

Relations

Items

Thumbnail Title Date Uploaded Visibility Actions
file details PDF of thesis T13726 2021-07-02 Public Download