Analytical Tools for Assessing Metabolic Activity in Biofilms

Biofilms play a fundamental role in a diversity of biological systems, including environmental ecosystems and human health. The metabolic activity of biofilms consists of an important determinant of their function and impact, playing a direct role in processes such as nutrient cycling, transfer of information, and consequently, their pathogenicity. Thus, understanding and determining the biofilm metabolism is essential for determining their behavior and creating effective strategies for their control and management. This chapter will delve into various methodologies for assessing the metabolic activity of biofilms, emphasizing the pivotal role they play in enhancing our comprehension of these microbial communities. For this purpose, enzymatic-related methods such as lactic acid evaluation and proteases will be detailed. Also, dye reduction-based assays including those related to the reduction of tetrazolium salts (i.e., XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assays) and resazurin will be covered in this chapter. Information on their applicability, procedures for implementation, shortcomings, and the specific mechanisms of each technique for determining biofilm metabolism will be detailed. The in-depth analysis presented in this chapter enhances the understanding of biofilm metabolic activity and its wide-ranging applications in diverse fields of science and technology.