Biofilm research using calorimetry--a marriage made in heaven?

Aggregated bacteria growing on a surface, so-called biofilms, play an important role in technical processes like wastewater treatment, bioremediation, or bioprocessing. In contrast, problems arise when biofilm growth results in undesired processes that may cause huge financial losses, e.g., clogged pipes, microbially influenced corrosion or pathogenic contamination. For observation purposes and to develop efficient control strategies, real-time monitoring tools for biofilms are required. Among the large variety of tools used in biofilm research, calorimetry is rarely applied, even though many characteristics qualify it for biofilm investigation and monitoring. Calorimetric measurements are non-invasive and non-destructive, and can be applied to nearly any kind of samples (including heterogeneous or turbid solutions) without the need of special sample preparation. Online and real-time data acquisition reduces the labor and facilitates high-throughput measurements. The following article is meant to introduce and promote calorimetry as a future tool in biofilm research. It attempts an assessment of common, existent monitoring tools and specifically addresses the potential of calorimetry in this field.