Project OPTIMO

Optimisation of sustainable sulphuric acid production for (bio)leaching processes in the waste sector (ATCZ291)

Project description and objectives

The aim of this one-year project was to optimise the biogenic production of sulphuric acid from elemental sulphur using mesophilic and thermophilic sulphur-oxidising bacteria (such as Acidithiobacillus thiooxidans, Acidithiobacillus caldus, Sulfobacillus acidophilus or Sulfobacillus thermosulfidooxidans) in batch experiments. The resulting acid was then used to regulate the pH of the biological leaching of metals from secondary raw materials. Zinc, as an example of a metal, was (bio)electrochemically recovered from solution. This innovative approach can contribute to improving resource efficiency in the waste sector.

Further, the biologically produced acid was used to regulate the pH of a heap leaching of, for example, e-scrap. Another goal was to use this produced biogenic sulphuric acid for a spent-medium leaching of two different waste materials. In order to remove the metals from the solution, a bioelectrochemical system was optimised on the one hand to deposit 90% zinc at the cathode, and on the other hand to recover 90% of the zinc from the bioleachate by fractional precipitation.

This project aimed to demonstrate the high potential of extremely acidophilic, sulphur-oxidising bacteria with regard to cost-effective and efficient biogenic sulphuric acid production. Cross-border cooperation was necessary, as the expertise of each individual partner is essential for successful project implementation. K1-MET has many years of experience in the field of metallurgical and environmental process development and contributes its knowledge of bioelectrochemical systems. BOKU has many years of experience in screening bacteria for bioleaching and parameter evaluation. The Czech partner MU is a well-known expert in acidophilic chemolithotrophic bacteria and has long experience in metagenomics and biochemical analyses.


Project duration:

01.01.2022 to 31.12.2022

Funding programme:

INTERREG V-A Austria-Czech Republic 2014-2020

Project consortium:

K1-MET GmbH (Coordination)
Masaryk University
University of Natural Resources and Applied Life Sciences, Vienna


The project OPTIMO - "Optimisation of sustainable sulphuric acid production for (bio)leaching processes in the waste sector" (ATCZ1291) - is co-financed by the European Regional Development Fund (Interreg V-A Austria-Czech Republic 2014-2020).

For information on the OPTIMO project, visit the project website at: