Which type of bacteria thrive at pH below 5.5?
pH adaptation shapes microbial diversity. Acidophiles thrive at pH below 5.5 often below 3, found acid mine drainage Rio Tinto, volcanic pools, fermented foods yogurt, gastric epithelium. Maintaining cytoplasm near neutrality around pH 6 involves highly impermeable tetraether lipid membranes, active proton extrusion via primary P type ATPases and secondary antiporters, cytoplasmic buffering with basic amino acids arginine, acid chaperones HdeA preventing periplasmic protein aggregation, and DNA repair systems resistant to depurination. Membrane proteins reduced proton channels, periplasm buffe
Ref: Prescott's Microbiology, 11th ed., Chapter 7: Acidophiles - Growth below pH 5.5.