Systems Biology of Microorganisms

Bioelectrochemical metal recovery for metal production, recycling, and remediation

BioelectroMET is a collaborative EU project that will provide a sustainable alternative for recovery, recycling and remediation of metals from the mining industry. The technology developed in the field of microbial fuel cells will be used to directly convert wastes from the mining industry into electricity for the recovery of metals.

The main aims of this project were:

1. To study the microbial ecology of sulfide mineral mines and acid mine drainage to select suitable candidates for use in a microbial fuel cell.
2. Test the activity of the selected microbes to attach on to the electrodes and their ability to survive in and utilize wastewater to generate electrons and energy.
3. With the combined effort of the consortium, to build a microbial fuel cell which can efficiently and selectively produce, recover, and remediate metals from streams of high and low metal concentrations.
4. Scale up the bioelectrochemical device and demonstrate on-site metal recovery at mining sites or metallurgical plants.

Systems biology of acidophile biofilms for efficient metal extraction

In collaboration with many research groups from all over Europe, this EU funded project will investigate biofilm formation on the surface of the world's most abundant copper mineral, chalcopyrite. By applying con focal microscopy, metatranscriptomics, metaproteomics, bioinformatics, and computer modelling we will model how acidophilic microorganisms interact with the copper mineral and each other. This knowledge will be applied to bioheap inoculation to shorten the lag phase between building industrial bioheaps and the release of copper. In turn, this will increase the economic feasibility and industrial interest in bioleaching as a sustainable technology.

The main aims of this project were:

1. Test the effects of biofilm formation on bacterial metabolism and bioleaching efficiency.
2. Model microbial colonization patterns and interactions within biofilms.
3. Discern the optimal inoculation strategy for efficient biofilm formation.
4. Optimize industrial copper dissolution from chalcopyrite.

Removal of chalcopyrite passivation layers (with Luleå University of Technology)

The copper mineral with the most reserves in the world is chalcopyrite. However, chalcopyrite biomining is hindered by the formation of a barrier layer on the surface, called 'passivation'. The nature of this layer and how it may be removed is being investigated to increase the efficiency of copper solubilization.

The main aims of the project were:

1. Simulate temperature profiles in bioleaching experiments under controlled redox potential in an electrochemical cell and in a redox controlled column reactor.
2. Characterize chalcopyrite surfaces from the different leaching environments by means of X-ray Photoelectron Spectroscopy (XPS) to determine the nature of the passivating layer.Analyze gene and/or protein expression for inorganic sulfur compound and ferrous iron oxidation by acidophilic microorganisms.
3. Test a conceptual flowsheet to remove passivating layers under conditions mimicking stirred tank and heap bioleaching.

Understand how acidophiles are able to grow at low temperature

An acid mine drainage stream biofilm situated 250 m below ground in the permanently cold Kristineberg mine, northern Sweden was investigated to understand how the microbial community is equipped for growth at low temperature and acidic pH. Metagenomic sequencing of the biofilm and planktonic fractions will identify the dominating microorganisms and their metabolic capacities.

The main aims of the project were:

1. Identify the total microbial community including uncultivable species and archaea in Kristineberg mine.
2. Link the potential metabolic pathways to the environmental conditions.Identify acidophile strategies for growth at low temperature.
3. Exploit their ability to grow at low temperature for bioremediation of mining wastewaters.

Biological membranes in extreme conditions: tetraether lipid membranes and their interactions with potassium

Acidophiles are microorganisms that have evolved to live under highly acidic conditions. They have an internal positive membrane potential, which appears to contribute to their metal-resistance and ability to live in acidic conditions. How this potential is generated and maintained is unclear. The interest in the acidophile membrane is not only theoretical – as due to their stability over wide-range of temperatures and acidities the membranes may be useful for biomedical applications (such as drug-carriers). This project is funded by a grant from the Crafoord Foundation and carried out in collaboration with Ran Friedman at Linnaeus University.

The main aims of the project were:

1. Use a computer-aided approach to model the interaction of acidophile membranes with potassium.
2. Create hypotheses as to how potassium generates an internal membrane potential.
3. Test growth at with low and high potassium concentrations in the laboratory.