Microbial dynamics and metabolic pathways in a two-phase anaerobic digestion system treating azo dye and sulfate

• Grant number: 20/11860-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: June 01, 2021
• End date: May 31, 2022
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Eugenio Foresti
• Grantee: Jean Maikon Santos Oliveira
• Supervisor: Jeppe Lund Nielsen
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Aalborg University (AAU), Denmark
• Associated to the scholarship: 18/24269-2 - Azo dye decolorization through fermentation and mineralization in an anaerobic-aerobic system, BP.DR

Abstract

Molecular mechanisms involved in reductive decolorization of azo dyes are unclear, especially in the presence of sulfate. We aim to investigate the microbial communities and their roles in the biodegradation of a model azo dye in a two-stages anaerobic digestion system fed with wastewater containing azo and sulfate. The acidogenic reactor was designed so that it could uptake high loads of dye and achieve near complete decolorization. This was accomplished by inhibiting sulfidogenesis and methanogenesis due to the low pH of this unit, so electrons from the co-substrate could be preferentially used to reduce azo compounds. Microbial biomass has been collected periodically and will be analyzed using 16S metabarcoding and shotgun metagenomics. We also propose to use differential coverage binning to recover high quality genomes from the sequenced metagenomes. Quantitative proteomics will be further employed to identify proteins putatively involved in the degradation of the azo dye. We hope that this integrated approach will broaden our understanding of the molecular mechanisms involved in the biodegradation of azo dyes and provide support to the design of treatment units that suit the needs of different types of wastewaters containing azo dyes. (AU)