## 3 Results
### Biotransformation of (4S)-(+)-Carvone (6)  
(4S)-(+)-carvone (6) was converted to (1R, 4S)-dihydrocarvone (7), (1S, 4S)-dihydrocarvone (8), and dihydrocarveols (9) and (10) (Scheme 2). Thus, as with the reduction of (4R)-(-)-carvone (1) described above, the reduction of the double bond followed by the carbonyl group was detected. Chromatograms of the standards and products obtained by biotransformation using a ground potato are shown in Figure 5. Products (7) and (8) were identified as (1R, 4S)-dihydrocarvone (7) and (1S, 4S)-dihydrocarvone (8) by means of gas chromatography by comparing the R\({}_{\rm f}\) values with the standards. Figure 4: Chromatograms. (**a**) Products obtained by biotransformation using carrots: R\({}_{\rm f}\) = 6.891, (1R,2R,4R)-dihydrocarveol (4) and (1R,2S,4R)-neodihydrocarveol (5); unreacted substrate: R\({}_{\rm f}\) = 7.035, (1R, 4R)-(+)-dihydrocarvone (2). (**b**) Standard: R\({}_{\rm f}\) = 7.114 (1R, 4R)-(+)-dihydrocarvone (2). Moreover, to confirm their structure, we attempted to separate them using column chromatography. By using eluents with a different composition, it was not possible to separate the carvone from the products (**7**) and (**8**) being formed. In addition to dihydrocarvons, alcohols (**9**) and (**10**) were also obtained by the stereospecific reduction of the carbonyl group. Unfortunately, due to the fact that they formed in minute amounts, they could not be isolated, thus their structures were indeterminable. The results detected via GC chromatograms are displayed in Table 4.  
Similar to (4_R_)-(-)-carvone (**1**), the biotransformation of (4_S_)-(+)-carvone (**6**) took place with each of the applied biocatalysts and a higher degree of conversion was observed when the enzymatic system from vegetables was used for the reaction. Furthermore, another common feature of the bioreduction process for both carvone enantiomers is that the comminuted potato resulted in a complete reaction of the substrate, and a high diastereoisomeric purity of 82%. Attractive biocatalysts turned out to be an apple of the \"Kortland\" variety and a pear, at which a 100% diastereomeric excess was seen with a relatively high degree of conversion. Celeriac was not as effective as a bioreactor as in the transformation of (4_R_)-(-)-carvone (**1**). Verifying the Biotransformation of (4_S_)-(+)-Carvone (**6**) over Time Using Potato as a Biocatalyst  
To determine the course of the biotransformation of (4_S_)-(+)-carvone (**6**) catalyzed by the enzymatic system of higher plants, shredded potato tubers were used as a biocatalyst. The samples were collected at 2, 4, 6, 8, 10, 12, 24, 28, and 48 h. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Biocatalyst** & **Substrate (\%)** & \multicolumn{4}{c}{**Products (\%)**} \\ \cline{3-6}  & & **(7) + (8)** & **de** & **(9) + (10)** & **de** \\ \hline _Daucus carota_ L. (carrot) & 92 & 7 + 0 & 100 & 0 + 1 & 100 \\ _Apium gravele_ L. var. _rapaceum_ (celeriac) & 81.6 & 16.6 + 0 & 100 & 0 + 1.8 & 100 \\ _Petroselinum sativrum_ Hoffm: (parsley) & 84.5 & 5.2 + 0 & 100 & 9.1 + 1.6 & 70 \\ _Solanum tubresum_ L. (potato) & 0 & 78.8 + 12.5 & 82 & 3.7 + 5 & 15 \\ _Beta vulgaris_ L. (beetroot) & 79.6 & 19.1 + 0 & 100 & 0 + 1.3 & 100 \\ _Malus pumila_ L.(apple) “Golden” & 91.4 & 7.4 + 0 & 100 & 0 + 1.2 & 100 \\ _Malus pumila_ L.(apple) “Kortland” & 58.6 & 38.4 + 0 & 100 & 0 + 1.8 & 100 \\ _Pyrus communis_ L.(pear) “Konferencja” & 61.2 & 37.5 + 0 & 100 & 0 + 1.3 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of the biotransformation of (4_S_)-(+)-carvone (**6**). Figure 5: Chromatograms. **(a**) Products obtained by biotransformation using potato: R\({}_{\rm f}\) =10.623, (15,45)-dihydrocarvone (**8**); R\({}_{\rm f}\) =10.872 (1\(R\),4_S_)-dihydrocarvone (**7**); R\({}_{\rm f}\) =10.986 dihydroxycarved (**9**); R\({}_{\rm f}\) =11.247 dihydroxycarved (**10**).