Naphthenic acids (NA) are naturally occurring carboxylic acids released from bitumen during oil sands processing. NA's are acutely toxic to aquatic organisms and are primarily removed by microbial degradation. The purpose of this study was to isolate microorganisms capable of NA degradation and to determine the extent of NA surrogate degradation by microbial communities.
To determine the NA-degrading ability of native microorganisms, microcosms were incubated with "c-labelled NA surrogates cyclohexane carboxylic acid (CCA), and decahydronaphthoic acid (DHNA), and " ~ ev0olut~ion was monitored. All microcosms degraded CCA however, previous exposure to NA's is necessary for DHNA degradation to occur.
Using NA's as the sole carbon source, two bacterial strains identified as Psc~lrdonloi7as species, were isolated from enrichment cultures, and NA degradation was monitored by GC-MS. Co-cultures degraded >99% of NA within 4 weeks. However each bacterium degraded 15% of the total NA mixture.