« Previous AbstractAn Electronic Nose for Royal Delicious Apple Quality Assessment - A Tri-layer Approach    Next AbstractMicrobial volatile emissions promote accumulation of exceptionally high levels of starch in leaves in mono- and dicotyledonous plants »

J Oleo Sci

Title:		A New Approach to Prepare Chiral Aroma: Asymmetric Oxidation of Ionols with a Heme Acquisition System A Derived from Symbiotic Fluorescent Bacteria
Author(s):		Ezoe S; Ueda K; Matsuo H; Nagaoka H; Akakabe Y;
Address:		"Graduate School of Sciences and Technology for Innovation, Yamaguchi University. Sanyo Foods Co., Ltd., Research and Development"
Journal Title:		J Oleo Sci
Year:		2022
Volume:		71
Issue:		12
Page Number:		1769 - 1775
DOI:		10.5650/jos.ess22277
ISSN/ISBN:		1347-3352 (Electronic) 1345-8957 (Linking)
Abstract:		"The aim of this study was to propose an alternative route for preparing chiral beta- and alpha-ionols by asymmetric oxidation with a heme acquisition system A (HasA) derived from symbiotic fluorescent bacteria as a biocatalyst. The HasA (6 g) in distilled water (300 mL) was stirred at 1150 rpm for 1 day at 40 degrees C. Subsequently, a secondary alcohol (0.77 mmol) as a substrate in 2% 2-propanol was added to the catalyst solution. After verifying that the oxidation proceeded to ca 50% using gas chromatography (GC), the reaction mixture was filtered, extracted, washed, and dried over. The extract was concentrated in vacuo and purified using silica gel column chromatography to yield the oxidized product and recover the unreacted alcohol. beta-Ionol was oxidized into beta-ionone in a conversion of ca. 50% in the presence of the HasA for three days, and the remaining alcohol was recovered and analyzed using chiral GC after acetylation. The HasA selectively catalyzed the asymmetric oxidation of beta-ionol with a preference for the (R)- form to recover (S)-beta-ionol with 96.4 +/-1.6% enantiomeric excess (ee). In addition, alpha-ionol was similarly oxidized into alpha-ionone in a conversion of ca. 50% for seven days, preferentially remaining (9S)-alpha-ionol with 97.9 +/- 0.2% ee. The characteristic aroma of (S)-beta-ionol obtained by the asymmetric oxidation with the HasA showed floral and fruity like, while the aroma of (9S)-alpha-ionol described as violet and sweet. In this study, we successfully developed a new approach to prepare enantiomerically pure (S)-beta- and alpha-ionols by the asymmetric oxidation with the HasA"
Keywords:		*Odorants *Butylated Hydroxytoluene Oxidation-Reduction Bacteria Ethanol 2-Propanol Heme asymmetric oxidation chiral aroma heme acquisition system A ionol norisoprenoid;
Notes:		"MedlineEzoe, Shiro Ueda, Kenji Matsuo, Hirotake Nagaoka, Hiroyuki Akakabe, Yoshihiko eng Japan 2022/12/05 J Oleo Sci. 2022; 71(12):1769-1775. doi: 10.5650/jos.ess22277"