Microbial profiling in dune infiltration

DNA sequencing has made enormous strides over the past few years. The technology has advanced to the point where is should be possible, on the basis of information from the DNA (and indirectly the RNA messenger) of microorganisms present in the water cycle, to provide advice regarding the influence of (a)biotic factors on microbial populations and microbial metabolic processes.


Dunea infiltrates pre-treated surface water in its dune area as part of the company’s drinking water production process. This pre-treated surface water contains substances, including chemical contaminants, that are degradable for microorganisms. Dunea wants to determine the identity and the contribution of the bacterial populations and metabolic processes that are responsible for the purification of the pre-treated water during its dune passage. This information is used for the purpose of comparing the microbial populations (numbers and diversity), in the event that the surface water is subjected to a different form of pre-treatment in the future. Besides the effects on the general and dominant bacteria present, there is a strong interest in identifying the microbial processes associated with the degradation of micropollutants during the dune infiltration process. The idea is to answer such questions through the application of genomic profiling of bacteria and transcriptomics by means of Next Generation Sequencing.


In 2016 and 2017 water samples were taken at a number of sites in the filtration area and the DNA sequence of the 16S rRNA gene of bacteria was determined, with the aim of gaining insight into the composition of the samples’ bacterial populations. In 2017, research will also be conducted into the extent to which metagenomic and metatranscriptomic analyses can be used to gain insight into the biochemical processes that may occur in the water during dune passage.


The research has shown that microbial profiling and metagenomics can be used as the basis for tailor-made advice in the water sector. The results of these analyses provide insight into changes in the bacterial composition and metabolic process during the dune infiltration of pre-treated surface water. The results can now be communicated to the end-user in a clear and relatively simple manner. Because of the presence of low concentrations of microorganisms in the water during dune passage, metatranscriptomics analyses of these water samples cannot yet be applied.