Revised MIND project deliverable available

Version 2 of MIND Project Deliverable D2.4 on bacterial presence and activity in compacted bentonites has just been added to the website.

The reported work had five main objectives:

1) Analysis of the clay environment with respect to composition of minerals, elements and diversity of organic carbon.  These characteristics may influence bacterial presence and activity differently in different clays.

2) Methods development regarding visualisation of bacteria in clays and analysis of diversity using nucleic acid sequencing methods.  The methodological challenge was the extraction of cells and nucleic acids from the clay materials.  The question if metagenome analysis reveal the same diversity as 16S rDNA gene sequencing does was also addressed.

3) Parallel with the work reported here, work with compacted bentonite specifically addressed the effect of wet density on sulphide producing activity.  A new compilation of all data was done and interpreted.

4) The compacted clay work indicated that sulphide reacts with clays and is immobilised.  Follow-up experiments with exposure of various bentonite clays to sulphide were performed to investigate if sulphide can degrade bentonite clays.

5) Previously, work with compacted bentonite was performed using radioactive sulphate (³⁵SO₄) which limited the possibility for downstream analysis.  Next generation experimental configuration, without radioactivity, was developed and tested.  This enabled investigation of bacterial presence, numbers and activity, swelling pressure effects and sulphide reactivity without the constrains imposed by the need to work with a radionuclide.

The report is available here and further information about the MIND project is available here.