Bacteria, a prerequisite for life on earth and nature's own sanitation workers. But in order for us to be able to use them in a controlled way and maximise utility, we need to understand how they work and what differentiates bacterial communities – something that has previously been difficult to calculate. With the help of a new methodology, researchers from Chalmers have found the solution.
Bacteria are found almost everywhere, both in nature and in the built environment. Many of them help us stay healthy and some make us sick. Some of them perform important work in our infrastructure, such as in a sewage treatment plant where the function is completely dependent on microorganisms breaking down pollutants, and in drinking water production where microbial growth plays an important role for water quality. But bacteria can also create problems; when it comes to concrete and metal structures, corrosion caused by microorganisms leads to enormous costs for society.
– To make the bacteria work for us, we must design systems that enable them to do what we want. To do that we need to understand the relationships between the systems we design, the bacterial communities that develop and the functions they perform, says Oskar Modin, Professor at the Department of Architecture and Civil Engineering.
Hill numbers create order in the jumble of indices
Oskar Modin and his colleagues are now presenting a method for assessing the difference in composition between different communities of microorganisms. The method is described in a recently published article in the scientific journal Microbiome.
– When we develop measures and techniques, we need to understand how they affect the microbial composition. This is usually done using mathematical indices that describe the differences between two microbial communities. There are a number of indices and different researchers have their favorites.
With the study "Hill-based dissimilarity indices and null models for analysis of microbial community assembly", the research group has tried to bring order to the index chaos. The researchers show that for some data, completely different conclusions are reached depending on which indices they choose to use, but what they now also have been able to show is that there is a solution to the problem.
– By analyzing their data with a family of indices that are based on something called Hill numbers, researchers can draw robust conclusions. We have also developed a freely available software that we and other researchers can use to calculate this type of index, Oskar continues.
Well-needed methodology
The results from the group's research are an important piece of the puzzle in order to be able to develop methods for controlling the composition and function of the complex microbial communities that occur in the built environment.
– Right now we are running projects that aim to improve the function of sewage treatment processes and understand corrosion of concrete in tunnels. The new methodology we have developed will give us significantly better opportunities to interpret data from experiments and samples, Oskar Modin concludes.
The study was performed at the division of Water Environment Technolgy, Department of Architecture and Civil Engineering at Chalmers and University of Gothenburg.
For more information
- Professor, Water Environment Technology, Architecture and Civil Engineering