Surface topography and mechanical properties of Rhodococcus ruber biofilms under combined exposure to ethoxylated nonylphenol and copper oxide nanoparticles
DOI:
https://doi.org/10.17072/1994-9952-2026-3-308-318Keywords:
biofilms, Rhodococcus, ethoxylated nonylphenol, copper oxide nanoparticle, atomic force microscopy, adhesion forces, exopolymeric matrixAbstract
In recent years, there has been growing interest in the potential synergistic effects of nanomaterials and toxic organic compounds on microbial biofilms, as well as in the mechanisms underlying biofilm resistance to such combined stress. Particular attention has been paid to the effects of low (sublethal) concentrations of nanoparticles, which may enhance the antimicrobial activity of organic toxicants while also inducing protective responses in microorganisms, leading to the development of resistance.
Atomic force microscopy (AFM) was used to investigate topographical and viscoelastic changes in cells within Rhodococcus ruber IEGM 1263 biofilms under exposure to a hormone-like xenobiotic, ethoxylated nonylphenol (ENP), and copper oxide nanoparticles (CuO NPs). It was found that, in the presence of ENP, the root mean square (RMS) roughness of rhodococcal cells did not differ significantly from the control but increased twofold under combined exposure to 1.0 g/L ENP and 0.001 g/L CuO NPs.
Force spectroscopy measurements revealed more than a twofold increase in adhesion force between the biofilm surface and the cantilever probe (from 5.3 ± 1.9 to 14.1 ± 5.2 nN) in the presence of ENP and CuO NPs. At the same time, the adhesive properties of the biofilm were largely determined by the presence of the extracellular polymeric matrix. Under complex chemical stress, a statistically significant (3.2-fold) increase in the Young's modulus of the cells was observed, indicating an increase in the rigidity of the cell wall.
The obtained results indicate adaptive restructuring of rhodococcal biofilms, which may serve as a basis for the formation of biocatalytic systems with enhanced functional stability under combined stress induced by organic and mineral xenobiotics.
References
1. Баяндина Е.А и др. Устойчивость коллекционных штаммов родококков к воздействию экотоксиканта – этоксилированного нонилфенола // Вестник Пермского университета. Сер. Биология. 2023. Вып. 4. С. 337–348. DOI: 10.17072/1994-9952-2023-4-337-348. EDN: EGMVIP.
2. Ившина И.Б. и др. Актиномицеты Rhodococcus ruber – ключевые и универсальные биоокислители газообразных алканов С2-С4 // Микробиология. 2025. Т. 94, № 1. С. 3–32. DOI: 10.7868/S3034546425010019. EDN: HEPVUL.
3. Ившина И.Б., Криворучко А.В., Куюкина М.С. Биоразнообразие и систематика микроорганизмов: учеб. пособие. Пермь, 2019. 304 с.
4. Каталог штаммов Региональной профилированной коллекции алканотрофных микроорганизмов / под ред. И.Б. Ившиной. М.: Наука, 1994. 163 с.
5. Bayandina E.A. et al. Resistance of Rhodococcus ruber biofilms to CuO nanoparticles depending on exopolymer matrix composition // Acta Biomedica Scientifica. 2022. Vol. 7, № 5 1. P. 100–109. DOI: 10.29413/ABS.2022-7.5-1.11. EDN: OSIPVT.
6. Bendinger B. et al. Physicochemical cell surface and adhesive properties of coryneform bacteria related to the presence and chain length of mycolic acids // Applied and Environmental Microbiology. 1993. Vol. 59, № 11. P. 3973–3977. DOI: 10.1128/aem.59.11.3973-3977.1993.
7. Corvini P.F., Schäffer A., Schlosser D. Microbial degradation of nonylphenol and other alkylphenols – our evolving view // Applied Microbiology and Biotechnology. 2006. Vol. 72, № 2. P. 223–243. DOI: 10.1007/s00253-006-0476-5. EDN: GJQHVS.
8. Dorobantu L.S., Goss G.G., Burrell R E. Atomic force microscopy: a nanoscopic view of microbial cell surfaces // Micron. 2012. Vol. 43, № 12. P. 1312–1322. DOI: 10.1016/j.micron.2012.05.005. EDN: MIGXEQ.
9. Flemming H.-C., Wingender J. The biofilm matrix // Nature Reviews Microbiology. 2010. Vol. 8. P. 623–633. DOI: 10.1038/nrmicro2415.
10. Ikuma K., Decho A.W., Lau B.L.T. When nanoparticles meet biofilms – interactions guiding the environmental fate and accumulation of nanoparticles // Frontiers in Microbiology. 2015. Vol. 6. Art. 591. DOI: 10.3389/fmicb.2015.00591.
11. Krivoruchko A., Nurieva D., Ivshina I. Extracellular polymeric substances produced by actinomycetes of the genus Rhodococcus for biomedical and environmental applications // International Journal of Molecular Sciences. 2026. Vol. 25, № 1. Art. 498. DOI: 10.3390/ijms25010498. ЕDN: IAZEDR.
12. Kuyukina M.S., Bayandina E.A., Ivshina I.B. Interactions of microbial biofilms with metal nanoparticles in the context of bioremediation // Folia Microbiologica. 2026. DOI: 10.1007/s12223-026-01459-5. EDN: VSREKR.
13. Kuyukina M.S. et al. Adaptations of Rhodococcus rhodochrous biofilms to oxidative stress induced by copper(II) oxide nanoparticles // Langmuir. 2025. Vol. 41, № 2. P. 1356–1367. DOI: 10.1021/acs.langmuir.4c03987. EDN: TKAQSJ.
14. Kuyukina M.S., Glebov G.G., Ivshina, I.B. Effects of Nickel nanoparticles on Rhodococcus cell surface morphology and nanomechanical properties // Nanomaterials. 2022. Vol. 12. Art. 951. DOI: 10.3390/nano12060951. EDN: GJWADT.
15. Lu D. et al. Behavioral disorders caused by nonylphenol and strategies for protection // Chemosphere. 2021. Vol. 275. Art. 129973. DOI: 10.1016/j.chemosphere.2021.129973. EDN: ZHJTSA.
16. Lu J. et al. Biodegradation of nonylphenol ethoxylates by Bacillus sp. LY capable of heterotrophic nitrification // FEMS Microbiology Letters. 2008. Vol. 280, № 1. P. 28–33. DOI: 10.1111/j.1574-6968.2007.01039x.
17. Miao L. et al. Low concentrations of copper oxide nanoparticles alter microbial community structure and function of sediment biofilms // Science of the Total Environment. 2019. Vol. 653. P. 705–713. DOI: 10.1016/j.scitotenv.2018.10.354.
18. Mishra S. et al. Biofilm-mediated bioremediation is a powerful tool for the removal of environmental pollutants // Chemosphere. 2022. Vol. 294. Art. 133609. DOI: 10.1016/j.chemosphere.2022.133609. EDN: RDXSCZ.
19. Pen Y. et al. Effect of extracellular polymeric substances on the mechanical properties of Rhodococcus // Biochimica et Biophysica Acta (BBA) – Biomembranes. 2015. Vol. 1848, iss. 2. P. 518–526. DOI: 10.1016/j.bbamem.2014.11.007. EDN: URKWKF.
20. Servos M.R. Review of the aquatic toxicity, estrogenic responses and bioaccumulation of alkylphenols and alkylphenol polyethoxylates // Water Quality Research Journal. 1999. Vol. 34, № 1. P. 123–178. DOI: 10.2166/wqrj.1999.005.
21. Xu W. et al. Unveiling the occurrence, ecotoxicity, risks, and removal of major nonylphenol ethoxylate alternatives in the aquatic environment // ACS ES&T Water. 2026. Vol. 6(4). P. 2033–2046. DOI: 10.1021/acsestwater.5c01293. EDN: HHSRWM.
22. Zhang J. et al. Biotransformation of nonylphenol ethoxylates during sewage treatment under anaerobic and aerobic conditions // Journal of Environmental Sciences (China). 2008. Vol. 20, № 2. P. 135–141. DOI: 10.1016/s1001-0742(08)60021-2.
23. Zhang W., Hughes J., Chen Y. Impacts of hematite nanoparticle exposure on biomechanical, adhesive, and surface electrical properties of Escherichia coli cells // Appl. Environ. Microbiol. 2012, Vol. 78, № 11. Р. 3905–3915. DOI: 10.1128/AEM.00193-12. EDN: RIZMDT.
