African tree yields promising bacterium
By Amélie Padioleau
A team of biologists at the French
Institute of Research for Development (IRD) has isolated a new strain of the bacterium Escherichia
coli from Shea cake, a by-product of the African karité tree. The bacterium could
potentially be used to produce compounds valuable to the chemical and food-processing
industries.
"One would never have thought
of this bacterium for such a purpose," says Marc Labat, a member of the IRD research
team, which specialises in microbial biotechnology.
Working jointly with scientists in
Burkina Faso and Tunisia, and the French Agricultural Research Institute (INRA), his team
discovered the new type of E. coli — a bacterium normally found in the stomach of
warm-blooded animals. Analysis showed that this so-called C2 strain could transform toxic
compounds (such as tannins) into non-acidic ones (such as phenol derivatives), which are
of use to the food and chemical industries.
Genetically modified strains of E.
coli are already used commercially to manufacture various proteins, such as insulin and
growth hormones, and could be used in the food industry as preservatives. The C2 strain of
E. coli is of particular interest to industrialists, as it could be used in similar
applications but without the need for genetic engineering. Products resulting from its use
could therefore be labelled as ‘natural’.
The genetic origin of this
particular C2 strain remains to be identified. “At present, we have two
hypotheses,” says Labat. “Either the part of the genome that displays this
characteristic is present, but not expressed, in the normal strain. Or the wild strain has
some extra elements in its genome.”
Highly prized in the cosmetic
industry, and having recently been approved as a substitute for cocoa butter in chocolate,
shea butter is being used increasingly widely. But together with this growing demand is an
increase in the residues resulting from processing. "The detoxifying potential of the
C2 strain of Escherichia coli opens up the way to better management of these toxic
wastes", says Labat.
Labat indicates that intellectual
property rights could potentially be sought for the enzymatic activity of the new
bacterial strain and, if this were to happen, his African colleagues would jointly own the
patent. The public nature of this research will also enable scientists in the African
countries involved to carry out related research projects. One possibility is that
residues left over from processing other plants, such as peanuts, could be treated in a
similar fashion.
© SciDev.Net 2002
