## 4 Discussion
### Chemical Compounds Detected by GC-Ms
[30] found that the content of 3-methylbutan-1-ol in cultures of _Bacillus_ sp. strain LPPC170, was 2.30 \(\pm\) 0.59%, while our results showed that the content of this alcohol in the volatile composition emitted by the tested _Bacillus_ species was lower at 0.63 \(\pm\) 0.06% for _B. subtilis_ and 0.45 \(\pm\) 0.04% for _B. thuringiensis_, while no 3-methylbutan-1-ol was found in _B. amyloliquefaciens_ (Table 1). [PERSON] et al. [51] identified n-heptadecane in a mixture of volatile organic compounds produced by _B. amyloliquefaciens_. [PERSON] et al. [43] also confirmed the presence of saturated hydrocarbons in cultures of _B. amyloliquefaciens_ and _B. subtilis_. The presence of alkanes in bacteria of the genus _Bacillus_ was also confirmed by the results of our chemical analyses (Table 1). The composition of volatile compounds produced by _Bacillus_ bacteria was found to be very rich in alkylpyrazine derivatives (e.g., 2-methylpyrazine) by [PERSON] et al. [23] in _B. amyloliquefaciens_ and _B. subtilis_, while [PERSON] et al. [41] found the presence of a large number of these pyrazine derivatives in _B. thuringiensis_. The presence of numerous representatives of this group of compounds in _B. amyloliquefaciens_, _B. subtilis_ and _B. thuringiensis_ is also evidenced by the results presented in Table 1 of this study. [PERSON] et al. [50] and [PERSON] et al. [49] identified 2,5-dimethylpyrazine in cultures of _Bacillus_ sp., and in our analyses, we also found high levels of this compound (23.94%-34.17%) in the three _Bacillus_ species studied (Table 1). In addition, [PERSON] et al. [43] identified di-methyltrisulphide in _B. subtilis_, which was also confirmed by the results of our analyses (Table 1). [PERSON] et al. [49] also found this sulphide in _Bacillus_ sp. In addition, [PERSON] et al. [48], [PERSON] et al. [50] and [PERSON] et al. [49] identified 1,2-di-methylsulfide in _Bacillus_ spp., while our studies showed that the sulphide in question was only present in _B. thuringiensis_ (Table 1). Furthermore, [PERSON] et al. [52] identified \(\alpha\)-pinene in _Bacillus_ spp. while the results of our work confirmed the presence of this monoterpene in cultures of the three _Bacillus_ species analysed, i.e., _B. amyloliquefaciens_, _B. subtilis and _B. thuringiensis_ (Table 1). It should also be noted that [PERSON] and [PERSON] [53] showed that the type of culture medium also had a significant influence on the composition of volatile organic compounds produced by _B. subtilis_. Based on a series of chemical analyses, it has been demonstrated that _Fusarium_ fungi produce sesquiterpenes and monoterpenes as well as alcohols, carbonyl compounds, carboxylic acids and esters [20; 30]. The volatile emissions of some _Fusarium_ species have also been found to contain numerous benzene and benzaldehyde chlorine-derivatives. The volatile composition emitted by fungi of the genus _Fusarium_ also includes monoterpenes, which are terpene formed by the combination of two isoprene units. Another group of volatile compounds found in the volatile emission of _Fusarium_ fungi are low-molecular-weight alcohols. [PERSON] et al. [30] reported an isopentanol content of 21.17 \(\pm\) 2.43% in _F. oxysporum kalimantanense_ LPPC130, while our results did not confirm the presence of this alcohol in _F. oxysporum_ cultures. [PERSON] et al. [30] stated that the volatile emission of _F. oxysporum kalimantanense_ LPPC130 had 3.67 \(\pm\) 0.58% isobutanol and 13.97 \(\pm\) 1.82% 2-methylbutanol. Our results confirmed the presence of these two alcohols in _F. oxysporum_, as their content in the cultures was the lowest at 0.32 \(\pm\) 0.03% and 0.84 \(\pm\) 0.07%, respectively (Table 2). [PERSON] et al. [20] identified benzaldehyde in the volatile emission of _F. oxysporum_, which was also found in our analyses, where a high content (25.83 \(\pm\) 1.61%) of this aromatic ketone was found. Chlorobenzene and benzaldehyde derivatives are a characteristic group of volatile compounds found in the volatile composition of _F. oxysporum_. [PERSON] et al.