Optimal pH for Growth of Bacteria

Optimal pH for Growth of Bacteria

Organism Minimum pH Optimum pH Maximum pH
Thiobacillus thiooxidans 0.5 2.0–2.8 4.0–6.0
Sulfolobus acidocaldarius 1.0 2.0–3.0 5.0
Bacillus acidocaldarius 2.0 4.0 6.0
Zymomonas lindneri 3.5 5.5–6.0 7.5
Lactobacillus acidophilus 4.0–4.6 5.8–6.6 6.8
Staphylococcus aureus 4.2 7.0–7.5 9.3
Escherichia coli 4.4 6.0–7.0 9.0
Clostridium sporogenes 5.0–5.8 6.0–7.6 8.5–9.0
Erwinia caratovora 5.6 7.1 9.3
Pseudomonas aeruginosa 5.6 6.6–7.0 8.0
Thiobacillus novellus 5.7 7.0 9.0
Streptococcus pneumoniae 6.5 7.8 8.3
Nitrobacter sp. 6.6 7.6–8.6 10.0

Note: Most bacteria grow over a pH range of approximately 3 units.