Anaerobic co-digestion of commercial laundry wastewater and domestic sewage in a pilot-scale EGSB reactor: The influence of surfactant concentration on microbial diversity

• Published in: International biodeterioration & biodegradation 2018-02, Vol.127, p.77-86
• Main Authors: Centurion, V.B., Moura, A.G.L., Delforno, T.P., Okada, D.Y., Dos Santos, V.P., Varesche, M.B.A., Oliveira, V.M.
• Format: Article
• Language: English
• Subjects: Alkylbenzene sulfonate; Alkylbenzenesulfonates; Anaerobic conditions; Anaerobic degradation; Anaerobic digestion; Anaerobic microorganisms; Archaea; Biodegradation; Cleavage; Communities; Community involvement; Consortia; Degradation; Expanded granular sludge bed (EGSB); Gene sequencing; Household wastes; Illumina sequencing; Laundry; Linear alkyl sulfonates; Linear alkylbenzene sulfonate; Linear alkylbenzene sulfonate (LAS); Microbial diversity; Microbiology; Microorganisms; Molecular chains; Next-generation sequencing; Reactors; rRNA 16S; Sewage; Sludge; Sludge bed; Stratification; Studies; Surfactants; Toxicity; Wastewater; Water treatment
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2017.11.017

Different molecular tools (PCR-DGGE, 16S rRNA high-throughput sequencing and sequencing of the bamA gene) were used to assess and compare the microbial diversity in a pilot-scale expanded granular sludge bed (EGSB) reactor used for the anaerobic co-digestion of commercial laundry wastewater and domestic sewage and subjected to increasing concentrations of linear alkylbenzene sulfonate (LAS). Using PCR-DGGE, a microbial stratification along the sludge bed of the reactor was observed. When analyzed using 16S rRNA gene sequencing, the samples exhibited high microbial diversity and richness, with the lowest Shannon index obtained for the highest concentration of surfactant. For the Bacteria domain, the genera Bellilinea, Syntrophus, Syntrophobacter, Cytophaga, Bacteroides and Synergistes were the most abundant, whereas for the Archaea domain, the genera Methanosaeta and Methanolinea were predominant. The Pseudomonas genus was the only genus that was predicted to be involved in all steps of surfactant degradation. Additionally, bamA gene sequencing indicated the presence of the species Syntrophorhabdus aromaticivorans, Desulfosarcina cetonica and Syntrophus aciditrophicus, which have genetic potential for the aromatic ring cleavage under anaerobic conditions. Therefore, despite the high toxicity of LAS under anaerobic conditions, the use of different molecular tools revealed the great diversity and richness of the microbial community from the granular biomass of the EGSB pilot reactor, indicating that a microbial consortium is necessary for complete LAS degradation. Additionally, the sequencing analysis of the bamA gene represents a step forward in the understanding of the core microbial community involved in aromatic ring cleavage for anaerobic digestion of real laundry wastewater, which may guide future studies. [Display omitted] •PCR-DGGE, 16S rRNA and bamA gene sequencing were used to microbial diversity study.•A microbial stratification along the sludge bed of the reactor was observed.•Higher concentration of surfactant resulted in lowest diversity index values.•Pseudomonas genus was the only one related to all steps of surfactant degradation.•bamA gene study indicated species with potential for the aromatic ring cleavage.