Answer: i would say that it was among one of the first bacteria discovered by Sergie Winogradsky.. .and that thay are With cells up to 200 microns in diameter, species of Beggiatoa are among the largest prokaryotes!
oh, and here is this -
All strains of freshwater Beggiatoa demonstrate the ability to grow heterotrophically in the presence of oxygen, yet this growth tends to be limited by the lack of catalase in Beggiatoa species. Their reaction for hydrogen sulfide oxidation is:
2H2S + O2 --> 2S0 + 2H2O