## 3 Results and Discussion
### Antimicrobial Activity of SEWS  
The SEWS exhibited limited antimicrobial activity (Table 4). _Curtobacterium flaccumfaciens_ PM-YT growth was inhibited the most as the first inhibition zone was observed at 0.313 mg/mL SWES (Table 5). The product was either weakly active or inactive against the remaining Gram (+) and Gram (-) bacteria. Among screened fungi, the highest inhibition was achieved against _Fusarium moniliforme_ ATCC 38932 with MIC of 0.625 mg/mL (Table 5). _F. moniliforme_ and _C. flaccumfaciens_ are plant pathogens causing significant economic losses. Regardless of the numerous antimicrobial agents available in the market, the propagation of these microorganisms is difficult to control, especially in organic agriculture where utilization of synthetic pesticides is not acceptable [78]. For comparison, the ethanol-wash solute obtained from rapeseed meal exhibited antifungal activity against all tested fungi including _Aspergillus niger_ ATCC 1015, _Aspergillus flavus_, _Penicillium_ sp., _Rhizopus_ sp., and _Fusarium moniliforme_ ATCC 38932 with MIC of 0.313 mg/mL [12]. The authors attributed this effect to glucosionides in the rapeseed meal ethanol-wash solute which, however, were not present in the SEWS (Tables 1 and 2).  
Owing to the high amount of phenols in the SEWS, the low antimicrobial activity was unexpected. It might be due to the composite nature of the material. Multiple constituents of the SEWS might interact with each other, forming complexes with structures and properties differing from single compounds. The antimicrobial activity of the sunflower was mainly attributed to chlorogenic acid, the biological activity of which as a single compound was found higher [79] than in a mixture [80]. Besides, a potential formation of compounds with higher molecular weights might slow the diffusion of the active compounds and decrease their solubility in solid media, thus affecting the size of the zones and, as a whole, the interpretation of results [81]. Although the agar-well diffusion  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Test Microorganism**} & \multicolumn{6}{c}{**Zone of Inhibition, mm**} \\ \cline{2-6}  & \multicolumn{6}{c}{**SEWS Concentration, mg/mL**} \\ \cline{2-6}  & **5.0** & **2.5** & **1.25** & **0.625** & **0.313** & **0.156** \\ \hline \multicolumn{6}{c}{Gram (+) bacteria} \\ \hline _Bacillus subtilis ATCC 6633 & 0 & 0 & 0 & 0 & 0 \\ _Bacillus cereus_ & 0 & 0 & 0 & 0 & 0 \\ _Bacillus amyloliquefaciens_ 4 BCL-YT & 8 & 0 & 0 & 0 & 0 \\ _Staphylococcus aureus_ ATCC 25923 & 0 & 0 & 0 & 0 & 0 \\ _Listeria monocytogenes_ ATCC 8632 & 0 & 0 & 0 & 0 & 0 \\ _Enterococcus faecalis_ & 0 & 0 & 0 & 0 & 0 \\ _Micrococcus luteus_ 2 YC-YT & 8 & 0 & 0 & 0 & 0 \\ _Curtobacterium flaccumfaciens_ PM-YT & 12 & 12 & 10 & 10 & 8 & 0 \\ \hline \multicolumn{6}{c}{Gram (-) bacteria} \\ \hline _Salmonella enteritidis_ & 0 & 0 & 0 & 0 & 0 & 0 \\ _Escherichia coli ATCC 8739 & 9 & 8 & 0 & 0 & 0 & 0 \\ _Proteus vulgaris_ ATCC 6380 & 0 & 0 & 0 & 0 & 0 \\ _Pseudomonas aeruginosa_ ATCC 9027 & 8 & 8 & 0 & 0 & 0 & 0 \\ \hline \multicolumn{6}{c}{Fungi} \\ \hline _Candida albicans_ NBIMCC 74 & 0 & 0 & 0 & 0 & 0 & 0 \\ _Saccharomyces cerevisiae_ & 0 & 0 & 0 & 0 & 0 & 0 \\ _Aspergillus niger ATCC 1015 & 10 & 8 & 0 & 0 & 0 & 0 \\ _Aspergillus flavus_ & 8 & 0 & 0 & 0 & 0 & 0 \\ _Fusarium moniliforme_ ATCC 38932 & 12 & 10 & 8 & 8 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Screening of sunflower meal ethanol-wash solute for antimicrobial activity against selected microorganisms.  
method is widely used to screen plant extracts for antimicrobial activity [82], more studies should be conducted to avoid inaccurate conclusions on SEWS antimicrobial properties. Current findings imply a potential significance of the SEWS as an antimicrobial agent which, however, should be further investigated by using other methods and approaches.