title: Abiotic Dominance and Microbial Modulation of Carbon Steel Corrosion in Bentonite under Repository-Relevant Conditions
design: Bentonite samples were used for the DNA extraction using the DNeasy PowerMax Soil Kit according to the manufacturers protocol and following the bentonite-proven protocol of (Engel et al., 2019a) but finishing with 1 ml of DNA extract. Eluted DNA was subsequently purified and concentrated to a final volume of 50 l using the Genomic DNA Clean & Concentrator kit (Zymo Research, USA) following the manufacturers protocol. This step helped to remove impurities and concentrate the DNA for downstream applications and was again verified before (Mijnendonckx et al., 2024). Negative control samples (blank isolation controls) were included in every DNA extraction round to monitor potential contamination. Extracted DNA was quantified using the Qubit 2.0 Fluorometer (Invitrogen, Life Technologies, USA) and used for 16S rRNA gene amplicon sequencing to reveal microbial composition of the samples.