Methanotrophs and methanogens in masonry

Area of Science:

• Microbiology
• Environmental Science
• Building Science

Background:

• Methanotrophs, methane-oxidizing bacteria, are crucial for methane cycling.
• Historical buildings provide unique microhabitats for microbial communities.
• The presence and activity of methanotrophs in building materials are not well understood.

Purpose of the Study:

• To investigate the occurrence and activity of methanotrophs in stone samples from historical buildings.
• To determine if stone samples can produce methane to support methanotroph growth.
• To identify the types of methanotrophs present and their relationship with methane production.

Main Methods:

• Sampling of stone from 19 historical buildings in Germany and Italy.
• Isolation and identification of methane-oxidizing bacteria strains.
• Quantification of methanotroph cell numbers and methane oxidation activity.
• Measurement of methane production rates in stone samples under non-oxic conditions.

Main Results:

• Methanotrophs were detected in 48 out of 225 stone samples, with an average of 20 CFU/g.
• Twelve strains belonging to Type II methanotrophs (Methylocystis, Methylosinus, Methylobacterium) were isolated.
• Methane production was detected in 23 out of 47 stone samples, indicating the presence of methane-producing microbes.
• Methanotrophs were found in almost all samples exhibiting methane production.

Conclusions:

• Methanotrophs are present in historical building stones and are capable of methane oxidation.
• Stone materials can generate methane, supporting the growth of methanotrophs.
• Methanotrophs in these environments likely depend on biogenic methane produced within or on the stone surfaces.