Use of metals to enhance lignocellulose degradation in a sulfate reduction environment: availability of trace metals and control of sulfide toxicity

• Grant number: 23/10377-6
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: December 01, 2023
• End date: November 30, 2024
• Field of knowledge: Engineering - Sanitary Engineering - Environmental Sanitation
• Principal Investigator: Marcelo Zaiat
• Grantee: Bárbara Franco Vieira
• Supervisor: Fernando González Fermoso
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Instituto de la Grasa (IG), Spain
• Associated to the scholarship: 21/09463-0 - Co-treatment of lignocellulosic waste and sulfate-rich wastewater with generation of molecules of high added value, BP.PD

Abstract

Lignocellulose-rich wastes are widely produced all over the world. Lignin is the most recalcitrant component and it is hardly degraded in an anaerobic environment. In an environment of sulfate reduction, cellulose hydrolysis generates hydrogen peroxide, which is essential for the performance of peroxidases, enzymes that promote lignin oxidation. However, the sulfide produced is toxic to methanogenic archaea and even to some sulfate-reducing bacteria. The use of metals can be applied to precipitate the sulfide as insoluble metal sulfides, reducing its toxicity and improving the quality of the generated biogas. Mine drainage (MD) is an effluent rich in sulfate and metals. The co-treatment of MD and lignocellulosic biomass (LB) with the production of value-added molecules would be important for the circular economy. Researches on the anaerobic degradation of lignin are scarce in the literature and the use of sulfate in this process is poorly understood. The feasibility of controlling sulfide toxicity and biogas purity, besides the bioavailability of trace metals in this type of system should be further investigated. This project aims at evaluating the effects of different concentrations of metals commonly found in MD in a biological sulfate reduction environment by applying fractional factorial design (FFD) in batch assays using LB as the electron donor. Finally, the feasibility of the application of the co-treatment of MD and LB to produce value-added molecules will be evaluated. (AU)