## 3 Results and Discussion
### Antimicrobial Activity of Kombucha Evaluation  
Sea buckthorn leaf extract, which is rich in polyphenols and has antioxidant properties, may enhance the therapeutic effects of kombucha. It is, therefore, very important to investigate the safety and efficacy of this drink against pathogenic bacteria to better understand its potential applications in the food industry and the health sector [59]. For this reason, it is essential to ensure its safety. In this study, the antimicrobial activity of kombucha after 10 days of fermentation was evaluated and is shown in Table 5. All tested bacteria were sensitive to fermented kombucha containing sea buckthorn leaf extract, and L4-100 showed a statistically significant (_p_ < 0.05) increase in antimicrobial potential with inhibition zones ranging from 16.0 (_P. aeruginosa_ ATCC 27853) to 19.80 (_S. saprophyticus_ ATCC 15305) mm.  
Green tea kombucha G-100, which does not contain sea buckthorn leaf extract, did not show antimicrobial activity against _E. coli_ ATCC8739, _S. aureus_ ATCC 25923, _or E. faecalis_ ATCC 19433, indicating that during sea buckthorn leaf extract fermentation formed higher content of antimicrobial substances than during green tea fermentation. The antimicrobial activity could be attributed to the synthesis of organic acids and plant-derived phenolic compounds, as well as the action of enzymes, proteins, and bacteriocins [60; 61]. In this study, the highest pH, lowest TA, and TPC were identified in green tea kombucha, which could explain its lower antimicrobial potential. Several studies described traditional green and black tea kombucha antimicrobial activity against _E. coli_, _S. epidermidis_, _S. aureus_, and _P. aeruginosa_[60; 61], while [PERSON] et al. [60] reported that non-traditional kombucha prepared from different herals showed stronger antimicrobial effect compared to traditional black and green tea kombucha. Sea buckthorn leaf extract (L4-100 at day 0) also showed antimicrobial activity against _S. aureus_ ATCC 25923 and _S. saprophyticus_ ATCC 15305. Janceva  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **Fermentation, Days** & \
\begin{tabular}{c} **Glucose,** \\ **\%** \\ \end{tabular} & **Fructose, \%** & **Saccharose, \%** &
\begin{tabular}{c} **Total Sacharide,** \\ **\%** \\ \end{tabular} & **TSS, \({}^{\circ}\)Brix** \\ \hline \multirow{8}{*}{G-100} & 0 & 0.05 \(\pm\) 0.00 b & 0.02 \(\pm\) 0.00 a & 8.74 \(\pm\) 0.41 ef & 8.81 \(\pm\) 0.41 bcd & 9.57 \(\pm\) 0.42 a \\  & 1 & 0.02 \(\pm\) 0.00 a & 0.05 \(\pm\) 0.00 b & 8.87 \(\pm\) 0.39 ef & 8.94 \(\pm\) 0.39 cd & 9.47 \(\pm\) 0.38 a \\  & 3 & 0.02 \(\pm\) 0.00 a & 0.07 \(\pm\) 0.00 d & 8.81 \(\pm\) 0.38 ef & 8.90 \(\pm\) 0.38 bcd & 9.51 \(\pm\) 0.37 a \\  & 5 & 0.14 \(\pm\) 0.00 h & 0.10 \(\pm\) 0.00 g & 8.74 \(\pm\) 0.35 ef & 8.98 \(\pm\) 0.35 cd & 9.54 \(\pm\) 0.43 a \\  & 7 & 0.35 \(\pm\) 0.00 o & 0.24 \(\pm\) 0.00 o & 8.08 \(\pm\) 0.29 de & 8.67 \(\pm\) 0.29 bcd & 9.43 \(\pm\) 0.41 a \\  & 10 & 0.25 \(\pm\) 0.00 l & 0.20 \(\pm\) 0.00 m & 7.83 \(\pm\) 0.28 cd & 8.28 \(\pm\) 0.28 abcd & 9.21 \(\pm\) 0.39 a \\ \hline \hline \end{tabular} Data values are expressed as means with the standard deviation (\(n=3\)). Different lowercase letters a-t in the column show that values are significantly different (_p_ < 0.05).  
\end{table}
Table 4: _[PERSON]_et al. [62] described sea buckthorn extract antibacterial activity against several bacteria, among them _S. aureus_, which is mostly related to polyphenolic compounds composition and quantity.