Biofilm quantification on stone surfaces: comparison of various methods

Area of Science:

• Environmental Microbiology
• Biotechnology

Background:

• Biofilms are microbial communities that can form on various surfaces, including stone.
• Accurate quantification of biofilm biomass is crucial for ecological and industrial applications.
• Existing methods for estimating biofilm biomass have limitations.

Purpose of the Study:

• To evaluate the efficacy of three methods for estimating biofilm biomass on stone surfaces.
• To compare estimated biomass with actual microbial biomass determined by cell culture.
• To identify reliable methods for biofilm quantification on stone.

Main Methods:

• Biofilm formation was induced on stone samples using cyanobacteria.
• Biomass was estimated using chlorophyll a content, fluorescein diacetate hydrolysis, and color change measurements.
• Actual microbial biomass was determined through cell culture for comparison.

Main Results:

• Fluorescein diacetate hydrolysis showed statistically significant differences from actual biomass, invalidating its use.
• Chlorophyll a content was a good estimator, but challenges in complete extraction from stone were noted.
• Color change determination proved to be a reliable method for quantifying biofilms on stone.

Conclusions:

• Color change measurement is a suitable method for quantifying stone biofilms.
• Chlorophyll a is a potentially useful, though not perfect, estimator.
• Fluorescein diacetate hydrolysis is not recommended for this application.