# Natural Compounds in the Battle against Microorganisms--Linalool
## 4 Microbial Biotransformation of Linalool
In turn, _Fusarium_ strains isolated from the fruits of the genus _Citrus_ growing in the Amazon rainforest were also used for the biotransformation of (\(\pm\))-linalool. After adding the substrate in the amount of 1 g/L to the grown culture, the transformation was carried out for 5 days. Different products were obtained depending on the strain used. The _Fusarium_ spp. 1D2 strain transformed linalool via epoxy into a mixture of _cis_- and trans_-furanoid linalool oxide (yield 39 and 37%, respectively). As a result of using the _Fusarium_ spp. 1C5 strain, _cis_-furanoid linalool oxide was obtained with a yield of 32% and a mixture of _cis_- and _trans_-pyranoid linalool oxide (yield of 12% and 2%, respectively). The _Fusarium_ spp. 1 DC5 and _F. concentric_ strains were able to epoxidate the terminal double bond in the linalool molecule to give 1-methyl-1-(4-methylpentyl)-oxiranemethanol with a yield of 42%. The _F. fujikuroi_ strain was able to cleave the vinyl fragment from the linalool molecule, converting it into 6-methylhept-5-en-2-one with a yield of 49%. The second product (in the amount of 10%) was also observed in the post-reaction mixture, resulting from the reduction in the carbonyl group, i.e., 6-methylhept-5-en-2-ol [86] (Scheme 5). **Scheme 4. ** Biotransformation of linalool by fungus from Brazilian fruits. **Scheme 5. ** Biotransformation of linalool by _Fusarium_ strains from citrus. A key reaction in the metabolism of linalool observed in animals, plants and microorganisms is the C-8 carbon hydroxylation reaction. In the case of microorganisms, this reaction can additionally be an intermediate step in the formation of cyclic ethers. Such mixtures of various compounds that are both cyclic ethers and a hydroxyl derivative of linalool have been observed during the biotransformation of racemic (\(\pm\))-linalool. In this case, the substrate was biotransformed in cultures of _A. niger_ ATCC 16404 (for 9 days), _A. niger_ DSM 821 (for 6 days), _Botrytis cinerea_ 5901/2 (for 9 days), _B. cinerea_ 02/FBII/2.1 (for 3 days) and _C. cassicola_ DSM 62475 (for 3 days). Three of them--_A. niger_ DSM 821, _B. cinerea_ 02/ FBII/2.1 and _C. cassicola_ DSM 62475--transformed linalool into a mixture of _trans_-(2\(R\),5_R_)- and _cis_-(25_,5_R_)-furanoid linalool oxide at efficiencies of 7.7, 24.9 and 81.6%, respectively, and a mixture of _trans_-(2\(R\),5_S_)- and _cis_-(25_,5_S_)-pyranolol linalool oxide at efficiencies of 17.4, 8.6 and 14.9%, respectively. In addition to the above-mentioned products, _A. niger_ DSM 821, _B. cinerea_ 02/FBII/2.1 strains carried out the hydroxylation of linalool to 8-hydroxylinalool with yields of 14.2 and 17.2%, respectively. In the case of _A. niger_ ATCC 16404 strain, only _cis_-(25_,5_R_)-furanoid linalool oxide was observed with a yield of 5.3% and 8-hydroxylinalool was observed with a yield of 21%. On the other hand, the _B. cinerea_ 5901/2 strain was unable to convert linalool to cyclic ethers, but it only carried out the substrate hydroxylation reaction to 8-hydroxylinalool with an efficiency of 60% [76]. 8-hydroxylinalool was also obtained as a result of the biotransformation of (\(\pm\))-linalool by the enzyme CYP111A2 isolated from _Novosphingobium aromaticitorans_[87]. _B. cinerea_ strains (5901/2, 5909/1 and 5899/4), which were grown on grape must of the Milller-Thurgau variety, were also used for the biotransformation of (\(\pm\))-linalool. The flasks containing the sterilized must were inoculated with the microorganism and incubated at 25 \({}^{\circ}\)C for 2 weeks. Linalool was added to the culture prepared in this way. The major product of the biotransformation (greater than 90%) was found to be 8-hydroxylinalool [88] (Scheme 6). The same derivative of linalool was also obtained when _Nicotiana tabacum_ \"Bright Yellow\" tissue culture was used for the biotransformation of linalool. Callus tissues obtained from the plant stem were pre-cultured for 3-4 weeks in medium containing 2 ppm 2,4-dichlorophenoxyoxyacetic acid and 2% sucrose.