Bacteria: masters of compromise

Calculating the golden mean is something economists in particular concentrate on. Biological evolutionary research is another area where the search is on for the situation where multiple opposing processes and criteria are in balance. Take, for instance, the optimum build of the panther: muscled for sprinting, but also light and limber enough to climb trees. When considering the evolution of bacteria, the ‘multi-criteria decision-making model’ of the Italian economist Pareto proves useful.

In a publication in Science last week, Groningen biologist Prof. Matthias Heinemann (Molecular Systems Biology), together with colleagues from ETH Zurich, queried which important characteristics are optimized by bacteria during evolution. To address this question, the researchers used labelled nutrients to investigate how bacteria utilize resources.

Three main criteria

Using Pareto’s mathematics, they were able to calculate that three main issues are involved in the evolution of microbial metabolism. In the first place bacteria must convert nutrients in such a manner as to be able to reproduce as potently as possible. In the second place bacteria must simultaneously have as much energy as possible available for daily life functions. In the third place the conversion of food to energy needs to be as effective as possible, in the fewest number of reaction steps possible.

Near optimum

The researchers discovered that the Pareto optimum for bacteria is not entirely reached, and that there actually is what could be called a ‘near Pareto optimum’. There is another compromise that needs to be reached, the aim of which is to achieve as great a degree of flexibility as possible in using nutrients, which is necessary in order to easily adapt to a changing environment.

Success in life

According to the researchers, more knowledge about the fundamental processes bacteria operate on is important, simply because their way of life is so successful that they can be found in every corner of the world. Heinemann: ‘But we also want to use bacteria more often in biotechnological processes in biobased industry. That will be easier to do if we know more about why they do what they do.’

Note for the press

More information: Prof. Matthias Heinemann

Reference: Multidimensional Optimality of Microbial Metabolism. R. Schütz, N. Zamboni, M. Zampieri, M. Heinemann, U. Sauer. Science, 2012, 336
http://dx.doi.org/10.1126/science.1216882