The document describes experiments to optimize growth conditions for sulfide-oxidizing bacteria from the Middle Island Sinkhole in order to isolate pure cultures of Beggiatoa species. Sediment cores were enriched and incubated under various conditions simulating aerobic, anaerobic, and microaerobic environments at both room temperature and temperatures resembling the sinkhole. After a month, growth of white filaments was observed under aerobic and microaerobic conditions but not anaerobic. The filaments grew better in the cold temperatures compared to room temperature where yellow clumps formed. Future work aims to isolate Beggiatoa species from the enrichments using gradient media mimicking the natural environment.