Research
The research groups - Biosphere
Université de Liège (ULg)
Laboratory of Biochemistry
Promotor: Feller, Georges
Presentation
The Laboratory
of Biochemistry (University of Liège, Belgium) concentrates
its research activities on the molecular adaptations of enzymes
from extremophilic (= organisms that prefer extreme environments)
organisms, mainly psychrophiles (= organisms that live at extremely
low temperatures) from Antarctic and Arctic, for nearly two decades.
Our main achievement was to provide the first nucleotide sequences,
molecular models and X-ray structures (the latter in collaboration
with Dr. R. Haser, CNRS, France) of cold-active enzymes.
We are currently investigating the structural determinants of
activity and stability in extremophilic enzymes by site directed
mutagenesis, the engineering of enzymatic properties by directed
evolution and the thermodynamic properties of these enzymes.
The enzymes investigated have a strong potential for biotechnological
applications.
In addition, the metabolic adaptations of microorganisms to grow
at very low temperatures are studied by proteomic approaches
of the cold-induced proteins in bacteria.
The group has a well-established expertise in protein chemistry,
including purification and characterization, protein engineering,
enzymology and biophysical analysis. The equipment available
allows to perform all research steps from production to fine
analysis and includes for instance fermentation units, analytical-
to pilot-size chromatographic units, 2D-electrophoresis, protein
sequencer, fluorimetry and circular dichroism appliances, differential
scanning calorimeter and isothermal titration calorimeter.
The Laboratory of Biochemistry belongs to the Department of Life
Sciences, ensuring an easy access to various equipments and expertise
in related fields such as microbiology, molecular biology, biocomputing,
mass spectrometry or physical chemistry.
The Laboratory of Biochemistry has participated to 3 previous
EU programs (2 coordination, 1 participation). The techniques
and heavy instruments directly available are particularly diversified
and the academic environment ensures a thoughtful training of
young researchers. The Laboratory has also developed fruitful
collaborations with private companies active in biotechnology
at both the national and European levels.
Activities
The research activities are devoted to biochemical, biophysical and proteomic studies of the molecular adaptations acquired by microorganisms to survive and grow at very low temperatures. Environmental samples are collected at the vicinity of polar bases from various biotopes (snow, ice, soil, mosses…) and microorganisms, mainly bacteria, are isolated from these samples. These microorganisms are selected for their ability to grow at low temperatures and to produce enzymes of biotechnological interest. Fast growing strains are subjected to a proteomic study in order to identify proteins that are over-expressed during growth at low temperatures (CIPs, cold induced proteins) and to draw a metabolic pattern of cold-growing cells. Selected enzymes are subjected to biophysical studies in order to identify the molecular adaptations of the protein structures allowing a high catalytic activity at low temperatures. The potential usefulness of these cold-active enzymes in biotechnology and of the psychrophilic bacteria in bioremediation is also evaluated.
Metabolic and molecular adaptations of polar microorganisms to life at low temperatures: biochemical, biophysical and proteomic approaches
Main field of activity in polar regions
The main research axis of our team is currently the study of enzymes produced by microorganisms living at extremely low temperatures (psychrophiles) collected during annual expeditions in Antarctica. These enzymes are model compounds for folding and stability studies but also offer considerable biotechnological potential as they are highly active at low temperatures and are easily inactivated by heat treatment.
List of projects
- Ecological impacts of
petroleum hydrocarbons on the Antarctic microbial loop. Evaluation
of the efficiency of psychrophilic microorganisms in bioremediation
treatment
(2005-2009) - Study
of the cold acclimation proteins (CAPs) produced by an Antarctic
psychrophilic bacterium (Pseudoalteromonas haloplanktis)
induced by growth at low temperatures.
(2004-2007) - Biophysical
aspects of protein adaptation to extreme temperatures: activity-stability
relationships in psychrophilic and thermophilic enzymes
(2004-2007) - Cold-adapted
xylanases and cross-linking enzymes in the food and feed
industries
(2003-2007) - Selection
of a psychrophilic bacterial starter for bioremediation of
contaminated soils and waste-waters in winter
(2003-2005) - Genome
sequence of the psychrophilic Antarctic bacterium Pseudoalteromonas
haloplanktis
(2002-2005)
Research Group Team
- Leader: Dr Georges Feller
- Post doctorate researchers: Salvino D’Amico – Tony Collins
- PhD researcher: Jean Claude Marx
- Involved partners: Dr. R. Haser, CNRS, France