sludge
DNA was extracted using Zymo Quick-DNA fungal/bacterial miniprep kit (Zymo Research, Irvine, CA). The primer pair 341F-805R was used to target the V3/V4 regions of the 16S rRNA of both bacteria and archaea. Library preparation was done using a Nextera XT DNA Library Prep Kit (Illumina, San Diego, CA). The Illumina MiSeq platform was used for sequencing the library by 300 base paired-end sequencing.