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Histamine (HIST) and other biogenic amines found in fish and fishery products accumulated by the action of bacterial amino acid decarboxylase cannot be decomposed and eliminated by heating or other chemical methods. A simple method for HIST elimination is proposed by a coupling reaction of the fungal amine oxidase (FAO) and bacterial aldehyde oxidase (ALOX) of acetic acid bacteria. As a model reaction, FAO oxidized benzylamine to benzaldehyde, which in turn was oxidized spontaneously to benzoic acid with ALOX. Likely, in HIST elimination, FAO coupled well with ALOX to produce imidazole 4-acetic acid from HIST with an apparent yield of 100%. Imidazole 4-acetaldehyde was not detected in the reaction mixture. In the absence of ALOX, the coupling reaction was incomplete given a number of unidentified substances in the reaction mixture. The proposed coupling enzymatic method may be highly effective to eliminate toxic amines from fish and fishery products.

The aim of this study was to propose an alternative route for preparing chiral β- and α-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°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. β-Ionol was oxidized into β-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 β-ionol with a preference for the (R)- form to recover (S)-β-ionol with 96.4 ±1.6% enantiomeric excess (ee). In addition, α-ionol was similarly oxidized into α-ionone in a conversion of ca. 50% for seven days, preferentially remaining (9S)-α-ionol with 97.9 ± 0.2% ee. The characteristic aroma of (S)-β-ionol obtained by the asymmetric oxidation with the HasA showed floral and fruity like, while the aroma of (9S)-α-ionol described as violet and sweet. In this study, we successfully developed a new approach to prepare enantiomerically pure (S)-β- and α-ionols by the asymmetric oxidation with the HasA.

d-Mannose isomerase (EC 5.3.1.7) catalyzing reversible conversion between d-mannose and d-fructose was found in acetic acid bacteria. Cell fractionation confirmed the enzyme to be a typical membrane-bound enzyme, while all sugar isomerases so far reported are cytoplasmic. The optimal enzyme activity was found at pH 5.5, which was clear contrast to the cytoplasmic enzymes having alkaline optimal pH. The enzyme was heat stable, and the optimal reaction temperature was observed at around 40-60 °C. Purified enzyme after solubilization from membrane fraction showed the total molecular mass of 196 kDa composing of identical 4 subunits of 48 kDa. Washed cells or immobilized cells were well functional at nearly 80% of conversion ratio from d-mannose to d-fructose and reversely 20%-25% of d-fructose to d-mannose. Catalytic properties of the enzyme were discussed with respect to the biotechnological applications to high fructose syrup production from konjac taro.

Due to the indigestibility, utilization of konjac taro, Amorphophallus konjac has been limited only to the Japanese traditional konjac food. Koji preparation with konjac taro was examined to utilize konjac taro as a source of utilizable carbohydrates. Aspergillus luchuensis AKU 3302 was selected as a favorable strain for koji preparation, while Aspergillus oryzae used extensively in sake brewing industry was not so effective. Asp. luchuensis grew well over steamed konjac taro by extending hyphae with least conidia formation. Koji preparation was completed after 3-day incubation at 30°C. D-Mannose and D-glucose were the major monosaccharides found in a hydrolyzate giving the total sugar yield of 50 g from 100 g of dried konjac taro. An apparent extent of konjac taro hydrolysis at 55°C for 24 h seemed to be completed. Since konjac taro is hydrolyzed into monosaccharides, utilization of konjac taro carbohydrates may become possible to various products of biotechnological interest. Fil: Adachi, Osao. Yamaguchi University; Japón Fil: Hours, Roque Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina Fil: Akakabe, Yoshihiko. Yamaguchi University; Japón Fil: Arima, Hideyuki. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Taneba, Rie. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Tanaka, Junya. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Kataoka, Naoya. Yamaguchi University; Japón Fil: Matsushita, Kazunobu. Yamaguchi University; Japón Fil: Yakushi, Toshiharu. Yamaguchi University; Japón

Gluconobacter frateurii CHM 43 have D-mannitol dehydrogenase (quinoprotein glycerol dehydrogenase) and flavoprotein D-fructose dehydrogenase in the membranes. When the two enzymes are functional, D-mannitol is converted to 5-keto-D-fructose with 65% yield when cultivated on D-mannitol. 5-Keto-D-fructose production with almost 100% yield was realized with the resting cells. The method proposed here should give a smart strategy for 5-keto-D-fructose production., Centro de Investigación y Desarrollo en Fermentaciones Industriales

An essential oil from dried "wakame" (Undaria pinnatifida), prepared by a simultaneous distillation extraction method, was analyzed by GC-MS, indicating the presence of one major component of volatiles. The volatile component was identified as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene by comparison with the GC-MS and NMR spectra of synthetic. The henicosahexaene showed a subtly marine aroma. (6Z,9Z,12Z,15Z)-1,6,9,12,15-Henicosapentaene was also detected as a minor polyene in the essential oils. It was suggested that these polyenes contribute to the characteristic aroma of the dried wakame.

An essential oil from the brown alga Sargassum thunbergii, prepared by a simultaneous distillation extraction method, contained in two types of volatile polyenes with a terminal double bond such as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene and (6Z,9Z,12Z,15Z)-1,6,9,12,15-henicosapentaene and with their saturated terminal structures such as (3Z,6Z,9Z,12Z,15Z,18Z)-3,6,9,12,15,18-henicosahexaene and (3Z,6Z,9Z,12Z,15Z)-3,6,9,12,15-henicosapentaene. These volatile polyenes were identified by comparison with the GC-MS and NMR spectra of synthetics. The polyenes with the saturated terminal structures were found in the brown algae for the first time.

A novel oxidation of D-pentonates to 4-keto-D-pentonates was analyzed with Gluconobacter Thailandicus NBRC 3258. D-Pentonate 4-dehydrogenase activity in the membrane fraction was readily inactivated by EDTA and it was reactivated by the addition of PQQ and Ca2+. D-Pentonate 4-dehydrogenase was purified to two different subunits, 80 and 14 kDa. The absorption spectrum of the purified enzyme showed no typical absorbance over the visible regions. The enzyme oxidized D-pentonates to 4-keto-D-pentonates at the optimum pH of 4.0. In addition, the enzyme oxidized D-fructose to 5-keto-D-fructose, D-psicose to 5-keto-D-psicose, including the other polyols such as, glycerol, D-ribitol, D-arabitol, and D-sorbitol. Thus, D-pentonate 4-dehydrogenase was found to be identical with glycerol dehydrogenase (GLDH), a major polyol dehydrogenase in Gluconobacter species. The reaction versatility of quinoprotein GLDH was notified in this study., Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo en Fermentaciones Industriales

Membrane-bound, pyrroloquinoline quinone (PQQ)-dependent glycerol dehydrogenase (GLDH, or polyol dehydrogenase) of Gluconobacter sp. oxidizes various secondary alcohols to produce the corresponding ketones, such as oxidation of D-sorbitol to L-sorbose in vitamin C production. Substrate specificity of GLDH is considered limited to secondary alcohols in the D-erythro configuration at the next to the last carbon. Here, we suggest that L-ribose, D- and L-lyxoses, and L-tagatose are also substrates of GLDH, but these sugars do not meet the substrate specificity rule of GLDH. The oxygen consumption activity of wild-type Gluconobacter frateurii cell membranes depends on several kinds of sugars as compared with that of the membranes of a GLDH-negative variant. Biotransformation of those sugars with the membranes was examined to determine the reaction products. A time course measuring the pH in the reaction mixture and the increase or decrease in substrates and products on TLC suggested that oxidation products of L-lyxose and L-tagatose were ketones with unknown structures, but those of L-ribose and D-lyxose were acids. The oxidation product of L-ribose was purified and revealed to be L-ribonate by HRMS and NMR analysis. Biotransformation of L-ribose with the membranes and also with the whole cells produced L-ribonate in nearly stoichiometric amounts, indicating that the specific oxidation site in L-ribose is recognized by GLDH. Since purified GLDH produced L-ribonate without any intermediate-like compounds, we propose here a reaction model where the first carbon in the pyranose form of L-ribose is oxidized by GLDH to L-ribonolactone, which is further hydrolyzed spontaneously to produce L-ribonate.

Eight-carbon (C8) volatiles, such as 1-octen-3-ol, octan-3-one, and octan-3-ol, are ubiquitously found among fungi and bryophytes. In this study, it was found that the thalli of the common liverwort Marchantia polymorpha, a model plant species, emitted high amounts of C8 volatiles mainly consisting of (R)-1-octen-3-ol and octan-3-one upon mechanical wounding. The induction of emission took place within 40min. In intact thalli, 1-octen-3-yl acetate was the predominant C8 volatile while tissue disruption resulted in conversion of the acetate to 1-octen-3-ol. This conversion was carried out by an esterase showing stereospecificity to (R)-1-octen-3-yl acetate. From the transgenic line of M. polymorpha (des6(KO)) lacking arachidonic acid and eicosapentaenoic acid, formation of C8 volatiles was only minimally observed, which indicated that arachidonic and/or eicosapentaenoic acids were essential to form C8 volatiles in M. polymorpha. When des6(KO) thalli were exposed to the vapor of 1-octen-3-ol, they absorbed the alcohol and converted it into 1-octen-3-yl acetate and octan-3-one. Therefore, this implied that 1-octen-3-ol was the primary C8 product formed from arachidonic acid, and further metabolism involving acetylation and oxidoreduction occurred to diversify the C8 products. Octan-3-one was only minimally formed from completely disrupted thalli, while it was formed as the most abundant product in partially disrupted thalli. Therefore, it is assumed that the remaining intact tissues were involved in the conversion of 1-octen-3-ol to octan-3-one in the partially disrupted thalli. The conversion was partly promoted by addition of NAD(P)H into the completely disrupted tissues, suggesting an NAD(P)H-dependent oxidoreductase was involved in the conversion.

Production of 4-keto-D-arabonate (4KAB) was confirmed in a culture medium of Gluconacetobacter liquefaciens strains, newly isolated from water kefir in Argentina. The strains rapidly oxidized D-glucose, Dgluconate (GA), and 2-keto-D-gluconate (2KGA), and accumulated 2,5-diketo-D-gluconate (25DKA) exclusively before reaching the stationary phase. 25DKA was in turn converted to 4KAB, and 4KAB remained stable in the culture medium. The occurrence of 4KAB was assumed by Ameyama and Kondo about 50 years ago in their study on the carbohydrate metabolism of acetic acid bacteria (Bull. Agr. Chem. Soc. Jpn., 22, 271-272, 380-386 (1958)). This is the first report confirming microbial production of 4KAB., Centro de Investigación y Desarrollo en Fermentaciones Industriales

The citrus fruit Setomi is a hybrid of Yoshiura ponkan (Citrus reticulate Blanco) and Kiyomi (Citrus unshiu Mrcov. x Citrus sinensis Osbeck). The essential oils from the peel of Setomi and its parent cultivars were obtained by a simultaneous distillation extraction technique. Comparing the essential oils of Setomi and its parent cultivars, it was found that the oil in the peel of Setomi consisted of characteristic aroma components from each parent cultivar. The principal component analysis of data, obtained with an electronic nose, indicated that the odor quality of Setomi was different from those of the parent cultivars.

D-Ribose and 2-deoxy-D-ribose were oxidized to 4- keto-D-ribonate and 2-deoxy-4-keto-D-ribonate respectively by oxidative fermentation, and the chemical structures of the oxidation products were confirmed to be as expected. Both pentoses are important sugar components of nucleic acids. When examined, purine nucleosidase activity predominated in the membrane fraction of acetic acid bacteria. This is perhaps the first finding of membrane-bound purine nucleosidase., Centro de Investigación y Desarrollo en Fermentaciones Industriales

4-Keto-D-arabonate (D-threo-pent-4-ulosonate) and 4-keto-D-ribonate (D-erythro-pent-4-ulosonate) were prepared from D-arabinose and D-ribose by two successive reactions of membrane-bound enzymes, D-aldopentose 4-dehydrogenase and 4-keto-D-aldopentose 1-dehydrogenase of Gluconobacter suboxydans IFO 12528. Alternatively, they were prepared from D-arabonate and D-ribonate with another membrane-bound enzyme, D-pentonate 4-dehydrogenase. Analytical data confirmed the chemical structures of the 4-pentulosonates prepared. This is the first report of successful enzymatic synthesis of 4-pentulosonates.

Long-chain aldehydes (LCA), such as pentadecanal (PD), (8Z,11Z)-heptadecadienal (HDD) and (8Z,11Z,14Z)-heptadecatrienal (HDT), were identified in the essential oils obtained from fresh green tobacco leaves (Nicotiana tabacum cv. BY2 and N. tabacum cv. MC). PD, HDD and HDT were found to be produced enzymatically from palmitic acid (PA), linoleic acid and α-linolenic acid, respectively. LCA-forming activity for PA changed during growth of tobacco leaves and was highest at flowering time.

A growth-promoting substance (GPS) for methylotrophic yeasts was purified from yeast extract. The purified GPS showed growth promotion by reducing the lag time of the growth of methylotrophic Candida boidinii, while the growth rate at the exponential phase was the same as that of growth without GPS. GPS was finally identified to be L-proline by the criteria of instrumental analysis and chemical shift assignments.

(−)-( 3R,4R )-3-Butyl-4-vinylcyclopentene [(−)- 1 ] was synthesized via (+)-( 1S,5R )-3-oxabicyclo [3,3,0] oct-6-en-2-one. Synthetic (−)- 1 coincided with the peak with later retention time of racemic (±)- 1 in a chiral GC (CP-Cyclodex 236M), while the natural 1 in essential oils from the marine brown algae, Dictyopteris prolifera and D . sp. was identical with the earlier retention time peak. Thus, the absolute configuration of the natural product in Dictyopteris oils was determined as (+)-( 3S,4S ) with ca 100% enantiomeric excess.

Eikenella corrodens produces autoinducer-2 (AI-2) in the mid log phase, and AI-2 activity decreases dramatically during the stationary phase. We investigated the mechanism underlying this decrease in AI-2 activity. To analyze the mechanism, we extracted and purified AI-2 from the supernatant of mid-log-phase culture. Simultaneously, the stationary-phase culture supernatant was fractionated by ammonium sulfate precipitation. On incubating purified AI-2 and 4-hydroxy-5-methyl-3(2H)-furanone (MHF) with each fraction, the 30% fraction decreased both AI-2 and MHF activities. The data suggest that AI-2 and MHF were rendered inactive in the same manner. Heat and/or trypsin treatment of the 30% fraction did not completely arrest AI-2 inactivation, suggesting that partially heat-stable proteins are involved in AI-2 inactivation. We observed that an enzyme converted MHF to another form. This suggests that E. corrodens produces an AI-2 inactivating enzyme, and that AI-2 can be degraded or modified by it.

In order to confirm the biosynthetic pathway to 1-octen-3-ol from linoleic acid, a crude enzyme solution was prepared from the edible mushroom, Lentinus decadetes. When the reaction was performed in the presence of glutathione peroxidase, which can reduce organic hydroperoxide to the corresponding hydroxide, the amount of 1-octen-3-ol formed from linoleic acid was decreased. At the same time, an accumulation of linoleic acid 10-hydroxide could be detected. The 10-hydroperoxide therefore seems to be an intermediate on the biosynthetic pathway.

Immobilized cells of Daucus carota transformed acetophenone into (S)-α-phenethyl alcohol by a stereoselective reduction pathway. Immobilized cells of Nicotiana tabacum also transformed the same substrate into the (S)-alcohol, but neither stereoselective reduction nor stereoselective oxidation was observed in the biotransformation process. (R)- and (S)-α-phenethyl alcohol of a high enantiomeric purity of > 99% ee can be prepared by the biotransformation of acetophenone with immobilized cells of Gardenia jasminoides and Daucus carota.

In our previous study, a new microbial reaction yielding 4-keto-D-arabonate from 2,5-diketo-D-gluconate was identified with Gluconacetobacter liquefaciens RCTMR 10. It appeared that decarboxylation and dehydrogenation took place together in the reaction. To analyze the nature of the reaction, investigations were done with the membrane fraction of the organism, and 4-keto-D-arabinose was confirmed as the direct precursor of 4-keto-D-arabonate. Two novel membrane-bound enzymes, 2,5-diketo-D-gluconate decarboxylase and 4-keto-D-aldopentose 1-dehydrogenase, were involved in the reaction. Alternatively, D-arabonate was oxidized to 4-keto-D-arabonate by another membrane-bound enzyme, D-arabonate 4-dehydrogenase. More directly, D-arabinose oxidation was examined with growing cells and with the membrane fraction of G. suboxydans IFO 12528. 4-Keto-D-arabinose, the same intermediate as that from 2,5-diketo-D-gluconate, was detected, and it was oxidized to 4-keto-D-arabonate. Likewise, D-ribose was oxidized to 4-keto-D-ribose and then it was oxidized to 4-keto-D-ribonate. In addition to 4-keto-D-aldopentose 1-dehydrogenase, the presence of a novel membranebound enzyme, D-aldopentose 4-dehydrogenase, was confirmed in the membrane fraction. The formation of 4-keto-D-aldopentoses and 4-keto-D-pentonates (4-pentulosonates) was finally confirmed as reaction products of four different novel membrane-bound enzymes., Centro de Investigación y Desarrollo en Fermentaciones Industriales

The ability of immobilized cells of Daucus carota to reduce enantioselectively organic foreign substrates has been examined. The immobilized plant cells reduced, with excellent enantioselectivity, prochiral ketone substrates such as keto esters, aromatic ketones and heterocyclic aromatic ketones, leading to the corresponding chiral secondary alcohols with an enantiomeric purity of 52–99% ee in a chemical yield of 30–63%.

(−)-( 3R,4R )-3-Butyl-4-vinylcyclopentene [(−)- 1 ] was synthesized via (+)-( 1S,5R )-3-oxabicyclo [3,3,0] oct-6-en-2-one. Synthetic (−)- 1 coincided with the peak with later retention time of racemic (±)- 1 in a chiral GC (CP-Cyclodex 236M), while the natural 1 in essential oils from the marine brown algae, Dictyopteris prolifera and D . sp. was identical with the earlier retention time peak. Thus, the absolute configuration of the natural product in Dictyopteris oils was determined as (+)-( 3S,4S ) with ca 100% enantiomeric excess.

A total of 39 aroma compounds were detected in the essential oil of Citrus nagato-yuzukichi Tanaka (nagato-yuzukichi) by gas chromatography-mass spectrometry (GC-MS). The essential oil was characterized by a high percentage of monoterpene hydrocarbons (12 components, 90.52%). The composition pattern of essential oil in C. nagato-yuzukichi was fairly similar to that of Citrus sudachi Hort. ex Shirai (Sudachi). Principal component analysis (PCA) of data obtained with an electronic nose indicated a variation of each oil along PC1. The oils of Citrus junos Tanaka (Yuzu) and Citrus sphaerocarpa Tanaka (Kabosu) showed a clear upward displacement as compared with those of C. nagato-yuzukichi and C. sudachi. However, in PC2, the oils of C. nagato-yuzukichi and C. sudachi showed a displacement in a negative direction and a positive one respectively.

Chlorogenate hydrolase (EC 3.1.1.42, CHase) was highly induced in mycelia of Aspergillus sojae AKU 3312 grown in Czapek medium containing either instant coffee powder or coffee pulp as inducer. No CHase formation was observed in the mycelia when cultivated without the inducer. CHase was purified readily from CHase-induced mycelia to high homogeneity, and the purified CHase revealed the molecular weight of 180,000 consisting of two identical subunits of 88 kDa. Equimolar quinate (QA) and caffeate (CA) were confirmed on hydrolysis of chlorogenate (CGA). The purified CHase was only useful for a laboratory scale hydrolysis of CGA. For practical QA and CA production using scaled up hydrolysis of vegetable extracts of natural CGA resources, the enzyme activity of purified CHase decreased and denatured irreversibly. Preparation of coffee pulp koji and its application to QA and CA production were proposed instead of purified CHase. When coffee pulp koji was heated at 60 degrees C for 30 min, CHase survived without any appreciable loss of enzyme activity while vegetative mycelial growth and spore germination were terminated. The heated coffee pulp koji thus prepared was effective itself as stable immobilized catalyst of CHase for QA and CA production from vegetable CGA resources such as coffee powders, coffee pulp, and others.

The essential oil from the shoots of the marine embryophyte, Zostera marina was prepared by simultaneous distillation-extraction. Volatile compounds in the oil were identified by GC and GC-mass spectrometry. The major constituents were phytol, hexadecanamide, octadecanamide, pentadecane, heptadecane, nonadecane, (8 Z , 11 Z )-heptadecadienal (HDD), (8 Z )-heptadecenal (HD), (9 Z , 12 Z , 15 Z )-octadecatrienal and (9 Z , 12 Z )-octadecadienal. HDD and HD were shown to be formed enzymatically from linoleic acid and oleic acid, respectively.

Bamboo vinegar solutions had pHs of 2.5 to 2.8, and the amounts of organic constituents were estimated to be 2.3 to 4.6% (w/w). Volatile organic compounds (28 components) were detected by GC-MS, and among of these, 11 compounds were common to three samples of bamboo vinegar. Perhaps acetic acid, 3-methyl-1,2-cyclohexadione, guaiacol, p-cresol, and syringol contributed to the characteristic odors (sour, smoky, and medicinal note) in bamboo vinegar.

Linoleic acid (LA) incubated with a homogenate of Lentinula edodes or Tricholoma matsutake mushroom significantly increased the amount of (R)-1-octen-3-ol. The alcohol was identified as (S)-10-HODE with 90-87% and >99% enantiomeric excess (ee), respectively. During the incubation of LA with these homogenates in the presence of glutathione-glutathione peroxidase (GSH-GPx), which can reduce hydroperoxy fatty acids to the corresponding hydroxy acids, the formation of (R)-1-octen-3-ol was significantly inhibited, whereas the amount of 10-hydroxy-(8E,12Z)-8,12-octadecadienoic acid (10-HODE) was significantly increased. The acid was identified as (S)-10-HODE with 92-88% ee and >99% ee, respectively. The decrease in the amount of alcohol was approximately the same as the increase in amount of HODE in both mushrooms. These results indicate a stereochemical correlation between (R)-1-octen-3-ol and (S)-10-hydroperoxy-(8E,12Z)-8,12-octadecadienoic acid [(S)-10-HPODE] in both mushrooms.

The long-chain aldehydes, (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, were concisely synthesized by using Grignard coupling, catalytic hydrogenation with the Lindlar catalyst, and oxidation with Dess–Martin periodinane as the key steps. Particularly, (8Z,11Z,14Z)-8,11,14-heptadecatrienal and (7Z,10Z,13Z)-7,10,13-hexadecatrienal both possessed a seaweed-like odor.

In higher plants, C6 and C9 aldehydes are formed from C18 fatty acids, such as linoleic or linolenic acid, through formation of 13- and 9-hydroperoxides, followed by their stereospecific cleavage by fatty acid hydroperoxide lyases (HPL). Some marine algae can also form C6 and C9 aldehydes, but their precise biosynthetic pathway has not been elucidated fully. In this study, we show that Laminaria angustata, a brown alga, formed C6 and C9 aldehydes enzymatically. The alga forms C9 aldehydes exclusively from the C20 fatty acid, arachidonic acid, while C6 aldehydes are derived either from C18 or from C20 fatty acid. The intermediates in the biosynthetic pathway were trapped by using a glutathione/glutathione peroxidase system, and subjected to structural analyses. Formation of (S)-12-, and (S)-15-hydroperoxy arachidonic acids [12(S)HPETE and 15(S)HPETE] from arachidonic acid was confirmed by chiral HPLC analyses. These account respectively for C9 aldehyde and C6 aldehyde formation, respectively. The HPL that catalyzes formation of C9 aldehydes from 12(S)HPETE seems highly specific for hydroperoxides of C20 fatty acids.

Immobilized cells of Gardenia jasminoides enantioselectively transformed acetophenone into the corresponding ( R )-alcohol by a two-step pathway involving initial reduction of the aromatic ketone to produce a mixture of ( R )- and ( S )-α-phenethyl alcohol followed by stereoselective oxidation of the ( S )-aromatic alcohol to produce acetophenone.

Immobilized cells of Daucus carota enantioselectively transformed aromatic ketones such as acetophenone and propiophenone, into the corresponding ( S )-alcohols with an optical purity of 89–99% ee in a chemical yield of 54–70%. Immobilized Gardenia jasminoides cells yielded the ( R )-alcohols with a 63–91% ee.

After the formation of dianions of a carboxylic acid with lithium diisopropylamide, oxygen was bubbled into the solution to produce 2-hydroperoxy acid. Then the reaction mixture was acidified with a 2 N HCl solution and subsequently elevated to 50 degrees C to afford the aldehyde with the loss of one carbon atom. Even saturated (C(10)-C(20)) and unsaturated (C(18:1)) carboxylic acids were converted into the odd aldehydes (C(9)-C(19), C(17:1)) in high yields. This conversion was found to be an efficient method for the preparation of carboxylic acids (Cn) to one-carbon degraded aldehydes (Cn-1) via 2-hydroperoxy acids.

When long-chain unsaturated fatty acids such as oleic, linoleic, and linolenic acid were incubated with crude enzymes from the marine green alga Ulva pertusa, the corresponding (R)-2-hydroperoxy acids were formed with a high enantiomeric excess (>99%).