Isolation of environmental nitrifiers using modifed solid medium
This study aims to address the current difficulties in cultivating nitrifying bacteria using solid media. We discovered the presence of toxic substances in three conventional gelling agents (agar, agarose, and gellan gum), which severely inhibit the growth of nitrifying bacteria on solid media. To overcome this, we developed a simple "washing" strategy to eliminate the toxicity from conventional solid media, and successfully utilized it to isolate multiple hard-to-culture nitrifying microorganisms from environmental samples. Specifically, we first generated six enrichment cultures of nitrifying microorganisms from three environmental samples using two different culture media. Subsequently, these six enrichment cultures were inoculated onto the "washed solid media". Following a period of incubation, the resulting colonies were transferred into liquid media. Finally, index PCR combined with Next-Generation Sequencing was utilized to sequence the strains that tested positive for nitrification activity in the liquid cultures. The sequencing results derived from this process constitute the data uploaded in this submission.