16S of enrichment culture: petroleum environment
Following the centrifugation of 50 mL clay suspension at 5000g for XX minutes, Genomic DNA was extracted from the resulting pellet utilizing the Qiagen soil extraction kit (Qiagen, 47014, Valencia, CA). Subsequently, PCR amplification of hypervariable regions in bacterial and archaeal 16S rRNA was conducted. This process employed the primers 16S rRNA V4 515F (GTGCCAGCMGCCGCGGTAA) - 806R (GGACTACHVGGGTWTCTAAT) for bacterial amplification and Arch519F (CAGCCGCCGCGGTAA) - Arch915R (GTGCTCCCCCGCCAATTCCT) for archaeal amplification. The PCR reactions utilized the Phusion High-Fidelity PCR Master Mix with GC Buffer (New England Biolabs; Cat. No. M0530). After electrophoresis on a 2% agarose gel for initial detection, the qualified PCR products underwent purification with magnetic beads (AMPure XP system; Beverly, USA) and were quantified  by Q-PCR. To ensure equal representation, PCR products with similar concentrations were mixed, thoroughly homogenized, and subjected to additional electrophoresis on a 2% agarose gel. The recovery of target bands was carried out using Qiagen's gel recovery kit. The TruSeq DNA PCR-Free Sample Preparation Kit was utilized for library construction. The constructed libraries were quantified using Qubit and Q-PCR. After qualifying the libraries, 16S rRNA gene sequencing was performed on the NovaSeq 6000 platform.