Biofilms are communities of microorganisms adhering to a surface and embedded in an extracellular polymeric
matrix, frequently associated with disease and contamination, and also used for engineering applications such as bioremediation.
A mixed biofilm formed by bacteria and fungi may provide an optimal habitat for addressing contaminated areas.
To exploit the potential of natural microbial communities consisting of bacteria and fungi, it is essential to understand and
control their formation. In this work, a method to discriminate among bacteria of genera Bacillus, Pseudomonas,
Rhodococcus with respect to the fungus Pleorotus in a biofilm by means of pyrolysis-gaschromatography-mass spectrometry
and multivariate analysis is reported. Methylated fatty acids were chosen as biomarkers of microorganisms in the
pyrolysates. In situ thermal hydrolysis and methylation was applied. Pyrograms were used as fingerprints, thus allowing
for the characterization of whole cells analyzed without any sample pretreatment. Normalized pyrographic peak areas
were chosen as variables for chemometric data processing. Principal components analysis was applied as a dataexploration
tool. Satisfactory results were obtained in analyzing a real biofilm. The influence of growth medium on whole
bacteria fatty acid cell composition was also explored.
Keywords: Analytical pyrolysis, GC-MS, chemometrics, PCA, direct analysis of whole cells.
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