Linalool biotransformation

The procedure is very easy to reproduce and to scale up. Bioconversion products can be easily isolated by evaporation of the extraction solvent (e.g. tert-butyl methyl ether). Table 12.4 summarizes the product concentrations, molecular conversion yields and enantioselectivities obtained during linalool biotransformation with C. cassiicola DSM 62475. 

Stereospecific Biotransformation of (/ )-Linaiooi by Corynespora cassiicola DSM 62475 into Linalool Oxides... 

The biotransformation of (/f,5)-Iinalool by fungi is a useful method for the preparation of natural linalool oxides. The stereospecific conversion of (J ,5)-linalool by Corynespora cassiicola DSM 62475 led to 5/f-configured furanoid linalool oxides and 55-configured pyranoid linalool oxides, both via bS -configured epoxylinalool as postulated intermediate (Figure 12.6). The biotransformation protocol affords an almost total conversion of the substrate with high enantioselectivities and a molar conversion yield close to 100% (Table 12.4). Pure linalool oxides are of interest for lavender notes in perfumery. ... 

Figure 12.6 Stereospecific biotransformation of (R,S)-linalool by C. cassiicola via the (6S)-configured epoxylinalools as postulated intermediates...

In 1977, a Pseudomonad was isolated from soil by enrichment culture technique with linalool as the sole source of carbon and energy [36]. The bacterial strain was later identified as Pseudomonas incognita and given the name linalool strain . It was also capable of growing on geraniol, nerol and limonene. The biotransformation of geraniol by this... 

Only few literature data are available about the fungal biotransformation of linalool and its acetates. As mentioned before, the biotransformation of linalyl acetate by Aspergillus niger isolated from garden soil was studied [39,40]. Part of the unmetabolised substrate was... 

The biotransformation of linalool by Botrytis cinerea has also been described [60]. After addition of linalool to botrytised must, a series of transformation products was identified (E)- (49) and (Z)-2,6-dimethyl-2,7-octadiene-l,6-diol (48), trans- (76) and cw-furanoid linalool oxide (77), trans- (78) and c/s-pyranoid linalool oxide (79) and their acetates (80, 81), 3,9-epoxy-p-menth-1 -ene (75) and 2-methyl-2-vinyltetrahydrofuran-5-one (66) (unsaturated lactone), Fig. (11). Quantitative analysis however, showed that linalool was predominantly (> 90%) metabolised to ( )-2,6-dimethyl-2,7-octadiene-l,6-diol (49) by B. cinerea. The other compounds were only found as by-products in minor concentrations. 

Another example of fungal bioconversion of linalool was described in literature the biotransformation by Diplodia gossypina ATCC 10936 [61]. A conversion scheme for the bioconversion of both (/ )-(-)- and (S)-(+)-linalool was proposed. 

Fig. (11). Biotransformation products of linalool by Botrytis cinerea (after [60])...

Tissue Cultures, Microbial Transformations.—Little success has rewarded the search for cell cultures that effectively biosynthesize monoterpenes de novo. The most impressive studies utilize cultures from a variety of Mentha spp. yields of oil were some 60 % (w/v) of those in the parent plants, but the monoterpene products were generally more oxidized (i.e. ketones extra C=C bonds predominated). In vitro, oxidation at C-3 of the menthane skeleton was also restricted, apparently owing to an inhibition of the enzymic reduction of the 4(8) double bond in the intermediates formed.925 926 Colchicine stimulated synthesis of essential oil by Mentha cultures.927 Iridoid glucosides have been produced by cultured cells of Gardenia spp.673 Menthone was biotransformed to neomenthol by Mentha suspension cultures,928 and Nicotiana lines oxidized linalool and its derivatives at C-10 to aldehydes and alcohols,929 and also foreign substrates such as a-terpineol (at C-6 and C-7) and /raw.s-/ -menthan-9-en-l-ol (at C-4 and C-10).930... 

Biotransformation of linalool was studied in grape must using three strains of Botrytis cinerea (5901/2 5901/1 5899/4). Capillary gas chromatography (HRGC) and coupled capillary gas chromatography-mass spectrometry (HRGC-MS) revealed predominant conversion (> 90 %) of linalool to (E)-2,6-dimethyl-2,7-octadiene-l,6-diol. 

FIGURE 19.13 Biotransformation of geraniol (271), citronellol (258), and linalool (206) by plant suspension cells of Catharanthus roseus. (Modi ed from Hamada, H. et al Biotransformation of acyclic monoterpenes by biocatalysts of plant cultured cells and Cyanobacterium, Proceedings of 48th TEAC, 2004, pp. 393-395.)... 

FIGURE 19.17 Biotransformation of linalool (206) by Pseudomonas incognita (Madyastha et al., 1977) and Streptomyces albus NRRL B1865. (Modi ed from David, L. and Veschambre, H., Tetrahadron Lett., 25, 543, 1984.)... 

A. niger isolated from garden soil biotransformed linalool and its acetates to give linalool (206), 2,6-dimethyl-2,7-octadiene-l,6-diol (8-hydroxylinalool (219a), a-terpineol (34), geraniol (271), and some unidenti ed products in trace amounts (Madyastha and Krishna Murthy, 1988a,b). 

FIGURE 19.19 Biotransformation products of linalool (206) by Botrytis cinerea. (Modi ed from Bock, G. etal., /. FoodScL, 51, 659, 1986.)... 

Demyttenaere, J.C.R. and H.M. Willemen, 1998. Biotransformation of linalool to furanoid and pyranoid lin-alool oxides hy Aspergillus niger. Phytochemistry. 47 1029-1036. 

Miyazawa, M., K. Yokote, and H. Kameoka, 1994b. Biotransformation of linalool oxide by plant pathogenic microorganisms, Glomerella cingulata. Proceedings of the 38th TEAC, pp. 101-102. 

Linalyl acetate can be found in many plants, however, it is in the highest concentration in the essential oil of Citrus aurantium spp. aurantium (Wichtel, 2002). As an ester, linalyl acetate is hydrolyzed in vivo by carboxylesterases or esterases to linalool (Figure 8.14), which is then further metabolized to numerous oxidized biotransformation products (see metabolism of linalool) (Bickers et al., 2003). 

FIGURE 14.23 Biotransformation of racemic fran -linalool oxide-pyranoid (217a and a ) and racemic cw-linalool-pyranoid (217b and b ) by Glomerella cingulata. (Modified from Miyazawa, M. et al., 1994a. Proc. 38th TEAC, pp. 101-102.)... 

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