## 3 Results and Discussion
### Antimicrobial Characteristics  
The antimicrobial properties of PBS films modified with chloroform extract and scCO\({}_{2}\) extract compared to those of neat PBS films are shown in Figure 4. An analysis of the antimicrobial activity of the films showed that the modification significantly affected the growth of the tested microorganisms: _E. coli_, _S. aureus_, and _C. albicans_. The unmodified PBS film did not exhibit antimicrobial activity and was used as a control sample (CFU/mL count in the range of 10\({}^{7}\)-10\({}^{6}\)). Films modified with the extracts, especially at a concentration \begin{table}
\begin{tabular}{c c} \hline \hline
**Sample** & **DPPH (\%)** \\ \hline PBS & 1.74 \(\pm\) 1.92 b \\ PBS-Chl 0.01 & 15.60 \(\pm\) 2.91 a \\ PBS-Chl 0.05 & 26.44 \(\pm\) 3.01 c \\ PBS-CO\({}_{2}\) 0.01 & 19.55 \(\pm\) 2.07 a \\ PBS-CO\({}_{2}\) 0.05 & 41.13 \(\pm\) 1.31 d \\ \hline \hline \end{tabular} Values are presented as the mean \(\pm\) standard deviation. Means with different lowercases are significantly different at \(p\) < 0.05.  
\end{table} 
Table 5: Radical scavenging activity of neat and modified PBS films. of 0.05 g per 1 g of PBS, significantly reduced the growth of microorganisms; this was particularly evident for _E. coli_ and _S. aureus_. The scCO\({}_{2}\) extract reduced a number of colony-forming units (CFU/mL) to a greater extent than the Chl extract, which may indicate that the components present in the CO\({}_{2}\) extract had stronger antimicrobial activity. The activity against _C. albicans_ was lower than that against the bacteria, but there was also a noticeable tendency for the number of CFU/mL to decrease as the concentration of the extracts increased. In conclusion, modifying PBS films with plant extracts, especially CO\({}_{2}\), significantly increases their antimicrobial potential, which may be useful in various applications, such as food packaging and medical materials. [PERSON] et al. [32] confirmed that PBS and its copolymer (PBS with 20 mol.% of polybutylene adipate) PBSA containing 7 or 10% of fungi chitosan oligosaccharide and crustacean chitosan were utilized as antimicrobial additives and demonstrated high (higher than 4.7 log) levels of activity towards _E. coli_. However, these biopolymers were developed by melt compounding. Similarly, carvacrol incorporated into the PBS matrix, also via melt compounding, was found to be effective against _S. aureus_ cells starting from the small addition of 4 wt%, but it could be active against _E. coli_ strains when 10 wt% was employed [10]. Similar research to our experiments was performed by [PERSON] et al. [11], who prepared PBS with active agents, such as thymol, kesum, and curry, incorporated into its matrix via the solvent-casting method. The authors confirmed that the addition of 10% of kesum and thymol led to the creation of films which were active against _S. aureus_. Sea buckthorn-based extracts from various parts of this plant (including the leaves, stem, soleus, and seeds) have been repeatedly tested to determine their antimicrobial properties [31]. [PERSON] et al., in their study, used an ethanolic extract of sea buckthorn in combination with carboxymethylcellulose to coat the paper. In a test of antimicrobial properties using a method of measuring zones of growth inhibition on the medium (disc diffusion), activity against both _S. aureus_ (as a representative of Gram-positive bac  
Figure 4: The number and standard deviations of bacterial and yeast cells after their incubation with PBS films and PBS films with additives. Bars with different markings (*—\(p\) < 0.05; **—\(p\) < 0.01; ***—\(p\) < 0.001). teria) and _Pseudomonas aeruginosa_ (as a representative of Gram-negative bacteria) was observed, but a stronger effect was observed against the latter [33]. Despite the use of different extraction solvents, these observations were in agreement with those achieved in this study. In contrast, [PERSON] et al.