## 3 Results and Discussion
### Degradation of Archeological Textiles by P. aeruginosa  
The _P. aeruginosa_ strains isolated from the textiles were also examined for their ability to form biofilms on archeological material samples, which served as the sole carbon source. Both strains colonized the textiles, forming biofilm after 3 days at the level 5.6 \(\times\) 10\({}^{5}\) (KP842564) and 5.9 \(\times\) 10\({}^{6}\) CFU/cm\({}^{2}\) (KP842565). Extending the incubation time to 5 days resulted in an increase in the number of biofilm cells by 1-2 log units (Table 2). SEM-EDX analysis of pre-Columbian textile colonized by both tested _P. aeruginosa_ strains showed decreases in oxygen content of 12% in the case of colonization by KP842564 and 5% by KP842565. This may be the result of bacterial bioadhesion and biofilm formation on the textile samples (Table 3). The metabolism of _P. aeruginosa_ inhabiting fabrics can cause changes in the content of elements, as has previously been reported for microbial communities growing on historical materials. [PERSON] et al. (2016) observed the activation of numerous metabolic pathways, including those regulating the production of primary and secondary metabolites, including metabolites associated with the deterioration of organic compounds. Analysis of the infrared absorption spectra of the archeological fibers before and after biofilm formation in comparison to contemporary alpaca fibers revealed significant changes in the molecular structure of the keratin (Figure 2). The spectral range between 1000 and 1170 cm\({}^{-1}\) is recommended for investigation of structural changes in wool fibers caused by various destructive factors, such as temperature, oxygen, light, and microorganisms ([PERSON], 2016; [PERSON], 2016). \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Textile Sample After Biofilm** & **Textile Sample after** \\  & **Formation by _P. aeruginosa_ & **Biofilm Formation by** \\  & **KF842564** & _P. aeruginosa_ & KP842565 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Microscopic and chemical analysis of archeological textile samples after biofilm formation by _P. aeruginosa_ isolates. All spectra for the archeological fibers showed distinctly stronger absorption near 1040 cm\({}^{-1}\) than in the case of the contemporary alpaca fibers, which may result from the oxidation of disulfide S-S bonds of cysteine and the formation of the two functional groups. The characteristic peak at 1040 cm\({}^{-1}\) represents cysteine acid (-SO\({}_{3}\)\({}^{-}\)) and the spectral signal at 1071 cm\({}^{-1}\) indicates cystine monoxide (-SO-S-) [19; 29]. This finding could be interpreted as evidence of extensive destruction of cysteine in these archeological keratin fibers. Disulfide bonds are the main chemical cross-linkage maintaining the keratin fiber's secondary structure [30; 31]. Cleavage of a large proportion of the disulfide bonds between its molecular chains causes a high degree of keratin degradation. The growth of microorganisms on an archeological textile may cause the weakening or loosening of its structure, odor emission, pH changes, aesthetic changes, staining and discolorations on the surface, the production of slimy substances, decreases in strength, and finally complete deterioration [32; 33]. Many bacteria that are present in these kinds of organic substrata grow using very low concentrations of nutrients and allow the development of micro-niches for the growth of other microorganisms. As a consequence, the biodeterioration of archeological materials can cause significant economic losses and the destruction of priceless cultural artefacts. Colonization and the development of biofilms by fungi and bacteria significantly modify the material. Microorganisms which form biofilm on textiles also degrade the cellulose and proteins, which are one of the main components of natural fibers such as cotton or wool [32].