An enzymatic tandem reaction to produce odor-active fatty aldehydes

Abstract

Aldehydes represent a versatile and favored class of flavoring substances. A biocatalytic access to odor-active aldehydes was developed by conversion of fatty acids with two enzymes of the α-dioxygenase pathway. The recombinant enzymes α-dioxygenase (α-DOX) originating from Crocosphaera subtropica and fatty aldehyde dehydrogenase (FALDH) from Vibrio harveyi were heterologously expressed in E. coli, purified, and applied in a coupled (tandem) repetitive reaction. The concept was optimized in terms of number of reaction cycles and production yields. Up to five cycles and aldehyde yields of up to 26% were achieved. Afterward, the approach was applied to sea buckthorn pulp oil as raw material for the enzyme catalyzed production of flavoring/fragrance ingredients based on complex aldehyde mixtures. The most abundant fatty acids in sea buckthorn pulp oil, namely palmitic, palmitoleic, oleic, and linoleic acid, were used as substrates for further biotransformation experiments. Various aldehydes were identified, semi-quantified, and sensorially characterized by means of headspace–solid phase microextraction–gas chromatography–mass spectrometry–olfactometry (HS–SPME–GC–MS–O). Structural validation of unsaturated aldehydes in terms of double-bond positions was performed by multidimensional high-resolution mass spectrometry experiments of their Paternò–Büchi (PB) photoproducts. Retention indices and odor impressions of inter alia (Z,Z)-5,8-tetradecadienal (Z,Z)-6,9-pentadecadienal, (Z)-8-pentadecenal, (Z)-4-tridecenal, (Z)-6-pentadecenal, and (Z)-8-heptadecenal were determined for the first time. Key points • Coupled reaction of Csα-DOX and VhFALDH yields chain-shortened fatty aldehydes. • Odors of several Z-unsaturated fatty aldehydes are described for the first time. • Potential for industrial production of aldehyde-based odorants from natural sources. Graphical abstract

Application of Aroma Precursors in Food Plant Raw Materials: Biotechnological Aspect

“…Обмін речовин жирних кислот і амінокислот із розгалуженим ланцюгом може слугувати попередником для біосинтезу летких ароматичних компонентів у більшості плодів. Жирні кислоти відіграють важливу роль у синтезі ефірів, що складаються із 2-, 4-і 6-вуглецевих ланцюжків, які виникають переважно в-окисненням жирних кислот [22]. De novo синтезовані вільні жирні кислоти сприяють утворенню ефірів у багатьох плодах [23].…”

“…De novo синтезовані вільні жирні кислоти сприяють утворенню ефірів у багатьох плодах [23]. Доведено, що ліпоксигенази (ЛОГ, лінолеат:кисень:оксидоредуктази КФ 1.13.11.12) та гідропероксидліази роблять свій внесок у розщеплення довголанцюгових жирних кислот до С 6альдегідів, які далі можуть перетворюватись альдегіддегідрогеназами до спиртів [22][23][24] і мають характерні аромати фруктів, плодів. Аромат є одним із найбільш важливих якісних показників баштанних культур.…”

Determination of double bond positions in methyl ketones by gas chromatography–mass spectrometry using dimethyl disulfide derivatives

“…Therefore, a multitude of mass spectrometric approaches use specific instrumental setups, such as ultraviolet photodissociation 10,11 or derivatization steps. Commonly utilized derivatizations include ozone‐induced fragmentation 12,13 and the Paternò–Büchi reaction 14–19 . For volatile substances like methyl ketones, methods based on gas chromatography–mass spectrometry (GC–MS) are predestined.…”

“…Commonly utilized derivatizations include ozone-induced fragmentation 12,13 and the Paternò-Büchi reaction. [14][15][16][17][18][19] For volatile substances like methyl ketones, methods based on gas chromatography-mass spectrometry (GC-MS) are predestined. Reported methods are based on Oisopropylidene derivatives, 20 trimethylsilyloxy derivatives, [21][22][23][24] polymethoxy methyl esters, 25 and pyrrolidines.…”

Biocatalytic Production of Odor-Active Fatty Aldehydes from Fungal Lipids

“…30,31 By a coupled enzymatic reaction using a cyanobacterial fatty aldehyde dehydrogenase (FALDH) and an α-DOX, C 16 −C 18 fatty acids were efficiently converted to a series of homologous carbon chain-shortened aldehydes. 32 In the current study, the latter biocatalytic approach was applied to characterize aldehydes from the biotransformation of the uncommon odd-chain fatty acid margaroleic acid [17:1(9Z)] that are of potential interest as odorants. Mortierella hyalina (MHY) was found to accumulate considerable amounts of margaroleic acid in its mycelium.…”