Sludge metagenome
bacteria: The hypervariable V3-V4 region, 338F (5'-ACTCCTACGGGAGGCAGCAG-3') /806R (5'-GGACTACHVGGGTWTCTAAT-3') primers. archaea: The hypervariable V4-V5 region, 24F10extF (5'-TGYCAGCCGCCGCGGTAA-3') /Arch958modR (5'-YCCGGCGTTGAVTCCAATT-3') primers.