Mycobacteria Isolated from Angkor Monument Sandstones Grow Chemolithoautotrophically by Oxidizing Elemental Sulfur

Researchers have discovered that Mycobacterium species isolated from the deteriorating sandstones of Angkor monuments in Cambodia exhibit remarkable metabolic versatility. These bacteria can grow both by oxidizing elemental sulfur (chemolithoautotrophically) and by consuming organic substances (chemoorganoheterotrophically). The study, involving five strains closely related to Mycobacterium cosmeticum and Mycobacterium pallens, focused on strain THI503, which demonstrated a significant decrease in medium pH during sulfur oxidation, confirming its role in energy metabolism. Fluorescence microscopy revealed that these bacteria adhere to and proliferate on sulfur particles, highlighting their adaptability in nutrient-limited sandstone environments. This dual metabolic capability suggests a potential mechanism for microbial contribution to stone deterioration.

Kusumi, A., Li, X. S., & Katayama, Y. (2011). Mycobacteria Isolated from Angkor Monument Sandstones Grow Chemolithoautotrophically by Oxidizing Elemental Sulfur. Frontiers in Microbiology, 2. https://doi.org/10.3389/fmicb.2011.00104