Martins Valdo R, Freitas Carlos J B, Castro A Rita, Silva Rita M, Gudiña Eduardo J, Sequeira João C, Salvador Andreia F, Pereira M Alcina, Cavaleiro Ana J
CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal.
Front Microbiol. 2021 Aug 19;12:618270. doi: 10.3389/fmicb.2021.618270. eCollection 2021.
Biosorbent materials are effective in the removal of spilled oil from water, but their effect on hydrocarbonoclastic bacteria is not known. Here, we show that corksorb, a cork-based biosorbent, enhances growth and alkane degradation by B4 (Ro) and SK2 (Ab). Ro and Ab degraded 96 ± 1% and 72 ± 2%, respectively, of a mixture of -alkanes (2 g L) in the presence of corksorb. These values represent an increase of 6 and 24%, respectively, relative to the assays without corksorb. The biosorbent also increased the growth of Ab by 51%. However, no significant changes were detected in the expression of genes involved in alkane uptake and degradation in the presence of corksorb relative to the control without the biosorbent. Nevertheless, transcriptomics analysis revealed an increased expression of rRNA and tRNA coding genes, which confirms the higher metabolic activity of Ab in the presence of corksorb. The effect of corksorb is not related to the release of soluble stimulating compounds, but rather to the presence of the biosorbent, which was shown to be essential. Indeed, scanning electron microscopy images and downregulation of pili formation coding genes, which are involved in cell mobility, suggest that cell attachment on corksorb is a determinant for the improved activity. Furthermore, the existence of native alkane-degrading bacteria in corksorb was revealed, which may assist bioremediation. Hence, the use of corksorb in marine oil spills may induce a combined effect of sorption and stimulated biodegradation, with high potential for enhancing bioremediation processes.
生物吸附材料在去除水中溢油方面很有效，但它们对烃类分解菌的影响尚不清楚。在此，我们表明，一种基于软木的生物吸附剂——软木吸附剂，能促进B4（Ro）和SK2（Ab）的生长及烷烃降解。在软木吸附剂存在的情况下，Ro和Ab分别降解了2 g/L正构烷烃混合物的96±1%和72±2%。相对于没有软木吸附剂的试验，这些值分别增加了6%和24%。这种生物吸附剂还使Ab的生长增加了51%。然而，与没有生物吸附剂的对照相比，在软木吸附剂存在的情况下，参与烷烃摄取和降解的基因表达未检测到显著变化。尽管如此，转录组学分析显示rRNA和tRNA编码基因的表达增加，这证实了在软木吸附剂存在的情况下Ab具有更高的代谢活性。软木吸附剂的作用与可溶性刺激化合物的释放无关，而是与生物吸附剂的存在有关，事实证明生物吸附剂是必不可少的。实际上，扫描电子显微镜图像以及参与细胞移动性的菌毛形成编码基因的下调表明，细胞在软木吸附剂上的附着是活性提高的一个决定因素。此外，还揭示了软木吸附剂中存在天然的烷烃降解细菌，这可能有助于生物修复。因此，在海洋溢油中使用软木吸附剂可能会产生吸附和刺激生物降解的联合效应，具有增强生物修复过程的巨大潜力。
