Sustainable pollutant removal by periphytic biofilm via microbial composition shifts induced by uneven distribution of CeO2 nanoparticles

• Published in: Bioresource technology 2018-01, Vol.248, p.75-81
• Main Authors: Tang, Jun, Zhu, Ningyuan, Zhu, Yan, Zamir, Seyed Morteza, Wu, Yonghong
• Format: Article
• Language: English
• Subjects: Microbial aggregates; Nanoparticle distribution; Nanotoxicity; Pollutant removal; STXM
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.07.064

[Display omitted] •CeO2 nanoparticles (NPs) distribution was detected by scanning transmission X-ray microscopy.•Uneven distribution of CeO2 NPs induced microbial community shifts.•Community composition of periphytic biofilm was investigated at phylum, class and genus level.•Pollutants removal was sustained via self-regulation of community composition. The responses of periphytic biofilm to CeO2 nanoparticle (CNP) exposure were explored by investigating community shifts and pollutant removal. Results showed that CNPs entered the sensitive microbial cells in the periphytic biofilm, leading to cytomembrane damage and intracellular reactive oxygen species (ROS) generation. The periphytic biofilm communities were, however, able to adapt to the prolonged exposure and maintain their pollutant removal (i.e., phosphorus, nitrogen and copper, organic matter) performance. Observations under synchrotron radiation scanning transmission X-ray microscopy revealed that fewer CNPs were distributed in algal cells compared to bacterial cells, wherein the transformation between Ce(IV) and Ce(III) occurred. High-throughput sequencing further showed that the proportion of algae, such as Leptolyngbya and Nostoc, significantly increased in the periphytic biofilm exposed to CNPs while the proportion of bacteria, such as Bacilli and Gemmatimonadetes, decreased. This change in community composition might be the primary reason for the sustained pollutant removal performance of the periphytic biofilm.