Biofilm microbial composition changes due to different surface chemical modifications of activated carbon cloths in the biotransformation of 4-nitrophenol
- 33 Downloads
Activated carbon cloths (ACCs) were used as biofilms supports in the anaerobic biotransformation of 4-nitrophenol (4NP). As received ACC material (AW) was oxidized with HNO3 (OX) and then functionalized with anthraquinone-2,6-disulfonate (AQ). The three ACCs were packed in hybrid UASB reactors and seeded with anaerobic granular sludge for biotransformation experiments. The results indicated that ACC-packed bioreactors improved the biotransformation of 4NP by twofold as compared to the control reactor without support materials. However, the biotransformation effciency of AW, OX and AQ was very similar (59%), indicating the role of ACC as biofilm support and not as redox mediator. After 4NP biotransformation several physicochemical and biological changes were observed like (1) the point of zero charge (pHPZC) shift from acidic values (AW = 5.0, OX = 3.4, AQ = 3.1) to neutral values (pHPZC = 7.6 on average), (2) increase in the concentration of acidic and basic surface functional groups over ACC materials and the amount of supported biomass on ACCs due to biofilm formation, and (3) enrichment of exoelectrogenic microorganisms belonging to the genera Geobacter over carbonyl-rich ACC surface as revealed by 16S rRNA amplicon sequencing. Overall, the results suggest that chemical modifications of ACCs changed the microbial composition of the biofilm, but the higher concentration of carbonyl groups on ACC did not affect the biotransformation of 4NP.
KeywordsActivated carbon cloth Point of zero charge Microbial composition changes Surface chemical modifications by biofilm
Authors greatly acknowledge the economic support provided by PAICYT (IT606-18) and PRODEP (UANL-CA-385). Juan Pablo held a fellowship from Consejo Nacional de Ciencia y Tecnología (CONACYT, CVU: 781364). Authors also recognize the help provided by students Alejandra Elizabeth Cabezas Camacho, Debanhi Susana Cantú Bedair, Susana Nanely Ibarra Robles, and Héctor Sepúlveda Briones. We also appreciate the general support from Dr. Felipe de Jesús Cerino Córdova and Dr. Eduardo Soto Regalado. SEM images in the supporting material section were kindly provided by Dr. Eduardo Maximiano Sánchez Cervantes and Dra. Nora Aleyda García Gómez.
- Kjelleberg S, Hermansson M (1984) Starvation-induced effects on bacterial surface characteristics. Appl Environ Microbiol 48:497–503Google Scholar
- Speece R (1996) Anaerobic biotechnology for industrial wastewaters. Archae Press, NashvilleGoogle Scholar
- Valero D, Rico C, Canto-Canché B et al (2018) Enhancing biochemical methane potential and enrichment of specific electroactive communities from nixtamalization wastewater using granular activated carbon as a conductive material. Energies 11:2101. https://doi.org/10.3390/en11082101 CrossRefGoogle Scholar
- van Loosdrecht MC, Lyklema J, Norde W, Zehnder AJ (1990) Influence of interfaces on microbial activity. Microbiol Rev 54:75–87Google Scholar