Main content area

Biodegradation of 1-adamantanecarboxylic acid by algal-bacterial microbial communities derived from oil sands tailings ponds

Paulssen, Julie M., Gieg, Lisa M.
Algal research 2019 v.41 pp. 101528
Chlorellales, Scenedesmus, algae, bacteria, biodegradation, bioremediation, cost effectiveness, laws and regulations, microbial communities, mine tailings, models, naphthenates, oil sands, photosynthesis, ponds, ribosomal RNA, sequence analysis, solid wastes, surface mining, toxic substances, toxicity, Alberta
Oil sands tailings ponds store millions of litres of water and solid wastes generated during the surface mining of oil sands deposits in Alberta, Canada. As government regulations mandate the ultimate reclamation of tailings ponds, toxic compounds within tailings, such as naphthenic acids, must be treated. Bioremediation holds promise as a cost-effective approach to treat compounds such as naphthenic acids in tailings ponds. While previous research showed that microorganisms (mainly bacteria) indigenous to tailings can biodegrade such compounds, most studies have used simple model compounds that do not always reflect the naphthenic acid composition of tailings ponds. Here, we assessed the ability for photosynthetic microbial communities derived from tailings ponds to biodegrade 1-adamantanecarboxylic acid, a model diamondoid naphthenic acid that has been detected in tailings ponds water and that has known recalcitrance and toxicity. Over the course of 90 days, the microbial communities were able to degrade this diamondoid NA by up to ~80% compared to controls. 16S and 18S rRNA gene sequencing showed that algae dominated the enrichments, with members of the order Chlorellales and the genus Acutodesmus (Scenedesmus) comprising ~90% of the relative sequence abundance. These data suggest that such algae played a key role in the biodegradation of 1-adamantanecarboxylic acid. This study demonstrates that algal communities present in oil sands tailings ponds have the potential to serve as remedial agents to treat the recalcitrant and toxic naphthenic acids in oil sands tailings ponds.