Chegounian Parisa, Flibotte Stephane, Peru Kerry, Headley John, McMartin Dena, Gramlich Bryne, Yadav Vikramaditya G
Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
UBC/LSI Bioinformatics Facility, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
Microorganisms. 2021 Oct 9;9(10):2124. doi: 10.3390/microorganisms9102124.
Naphthenic acid fraction compounds (NAFCs) are highly recalcitrant constituents of oil sands tailings. Although some microorganisms in the tailings can individually and synergistically metabolize NAFCs, the biochemical mechanisms that underpin these processes are hitherto unknown. To this end, we isolated two microorganisms, and , from oils sands tailings and analyzed their transcriptomes to shed light on the metabolic processes employed by them to degrade and detoxify NAFCs. We identified 1048, 521 and 1434 genes that are upregulated in , and a 1:1 co-culture of the strains, respectively. We subsequently enumerated the biochemical activities of enriched genes and gene products to reveal the identities of the enzymes that are associated with NAFC degradation. Separately, we analyzed the NAFCs that are degraded by the two pseudomonads and their 1:1 co-culture and determined the composition of the molecules using mass spectrometry. We then compared these molecular formulas to those of the cognate substrates of the enriched enzymes to chart the metabolic network and understand the mechanisms of degradation that are employed by the microbial cultures. Not only does the consortium behave differently than the pure cultures, but our analysis also revealed the mechanisms responsible for accelerated rate of degradation of NAFCs by the co-culture. Our findings provide new directions for engineering or evolving microorganisms and their consortia for degrading NAFCs more stably and aggressively.
环烷酸馏分化合物（NAFCs）是油砂尾矿中极难降解的成分。尽管尾矿中的一些微生物能够单独或协同代谢NAFCs，但支撑这些过程的生化机制迄今尚不清楚。为此，我们从油砂尾矿中分离出两种微生物，并分析它们的转录组，以揭示它们用于降解和解毒NAFCs的代谢过程。我们分别鉴定出在菌株、菌株和1:1菌株共培养物中上调的1048个、521个和1434个基因。随后，我们列举了富集基因和基因产物的生化活性，以揭示与NAFC降解相关的酶的身份。另外，我们分析了两种假单胞菌及其1:1共培养物降解的NAFCs，并使用质谱法确定了分子组成。然后，我们将这些分子式与富集酶同源底物的分子式进行比较，以绘制代谢网络并了解微生物培养物所采用的降解机制。不仅共生体的行为与纯培养物不同，而且我们的分析还揭示了共培养物加速NAFCs降解速率的机制。我们的研究结果为改造或进化微生物及其共生体以更稳定、更高效地降解NAFCs提供了新的方向。
