Cyanide degrading microbiomes at former gas plant sites – characterisation, enrichment and strain isolation

Beschreibung

Background information
Cyanides are frequently found at former gas plant sites, where they can form long plumes in the groundwater. After petroleum hydrocarbons like diesel and Polyaromatic Hydrocarbons (PAH) were reme-diated, cyanides often become the dominant contaminant. Many microorganisms are able to degrade cyanides in free and complexed forms (Alvillo-Rivera et al. 2021), however a detailed understanding of cyanide degrading bacterial communities at former gas plant sites that facilitates their application in bioaugmentation is still missing. We therefore work on the characterisation, enrichment and isolation of cyanide degrading microbiomes with the aim of testing their use for bioaugmentation in pilot test.
Main results
Enrichment cultures inoculated with samples (groundwater, soil, bac-trap-material) from four contami-nated sites in Austria and Germany were established. Original samples and enrichment cultures were characterised in respect to bacterial composition and degradation capacities of the enrichment cultures were determined in microcosms under different conditions (e.g., different pH; addition of PAHs and BTEX). In the groundwater samples Pseudomonas, Thiobacillus and Rhodococcus were the dominant genera that contain species described as cyanide degraders in literature. In the enrichment cultures Pseudomonas was the dominant genus followed by Burkholderia. Cell growth of enrichment cultures under elevated KCN was better at pH 8 compared to a pH around 7. Cyanide degradation in microcosms was not correlated with the formation of biomass. Cyanide degradation was inhibited by elevated concentrations of a mixture of Polyaromatic Hydrocarbons (PAH) and BTEX (benzene, toluene, ethylbenzene and xylene).
About 1 400 strains were isolated from the enrichment cultures and a selection of them will be fully sequenced. Based on whole genome sequences, synthetic communities will be generated and tested for cyanide degradation. With the three best performing enrichment cultures a transcriptomics-experiment was performed by comparing gene expression with ammonia or cyanide as nitrogen source. These experiments were ongoing during the application of this abstract, however results will be ready to be presented at the conference.
Conclusions
Cyanide degrading cultures could be enriched and characterised from environmental samples from former gas plant sites. Cyanide degradation might be inhibited by elevated concentrations of PAHs and BTEX and toxicity of cyanides for bacteria is influenced by pH. The enrichments are further characterised by transcriptomics and full genome sequencing to identify the active species and genes. Preliminary data of these experiments will be available for presentation. Currently pilot tests are planned to test the efficiency of cyanide degradation of the enrichment cultures under field conditions.
Acknowledgements: The financial support of project MIBIREM (contract No. 101059260) by the European commission and of the project MIBICYD (contract No. C120007) by the Austrian Federal Ministry for Climate; project management by Kommunalkredit Public Consulting (KPC) are greatly appreciated.
References:
Alvillo-Rivera, A., S. Garrido-Hoyos,G. Buitrón, P. Thangarasu-Sarasvathi and G.Rosano-Ortega “Biological treatment for the degradation of cyanide: A review”, J. Mat. Res. Techn., 12: 14

Zeitraum	17 Juni 2025
Ereignistitel	9th European Bioremediation Conference
Veranstaltungstyp	Konferenz
Ort	Chania, GriechenlandAuf Karte anzeigen
Bekanntheitsgrad	International