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To quantitatively hydroxylate 8S- and 10S-positions on polyunsaturated fatty acids by recombinant Escherichia coli cells expressing mouse arachidonate 8S-lipoxygenase (8S-LOX). Hydroxylated products gained from the conversion of arachidonic acid (20:4Δ5Z,8Z,11Z,14Z, AA), eicosapentanoic acid (20:5Δ5Z,8Z,11Z,14Z,17Z, EPA), and (22:6Δ4Z,7Z,10Z,13Z,16Z,19Z, DHA) by recombinant E. coli cells containing 8S-LOX from mouse were identified as 8S-hydroxy-5,9,11,14(Z,E,Z,Z)-eicosatetranoic acid (8S-HETE), 8S-hydroxy-5,9,11,14,17(Z,E,Z,Z,Z)-eicosapentanoic acid (8S-HEPE), and 10S-hydroxy-4,8,12,14,16,19(Z,E,Z,Z,Z,Z)-docosahexaenoic acid (10S-HDoHE), respectively. Under the optimal hydroxylation conditions of pH 7.5, 30 °C, 5% (v/v) ethanol, 15 g cells l−1, and 5 mM substrate, AA, EPA, and DHA were hydroxylated into 4.37 mM 8S-HETE, 3.77 mM 8S-HEPE, and 3.13 mM 10S-HDoHE for 60, 90, and 60 min, with 87, 75, and 63% molar conversions, respectively. To the best of our knowledge, this is the first quantitatively biotechnological production of 8S-HETE, 8S-HEPE, and 10S-HDoHE.

This study was conducted to characterize recombinant α-l-rhamnosidase from Chloroflexus aurantiacus and apply the enzyme in the production of isoquercitrin from rutin. The α-l-rhamnosidase from C. aurantiacus was cloned and expressed in Escherichia coli BL21 and purified as a soluble enzyme. α-l-rhamnosidase purified from C. aurantiacus has a molecular mass of approximately 105 kDa and is predicted to exist as a homodimer with a native enzyme of 200 kDa. The purified enzyme exhibited the highest specific activity for rutin among the reported isoquercitrin producing α-l-rhamnosidases and was applied in the production of isoquercitrin from rutin. Under the optimised conditions of pH 6.0, 50 °C, 0.6 U mL−1 α-l-rhamnosidase, and 30 mM rutin, α-l-rhamnosidase from C. aurantiacus produced 30 mM isoquercitrin after 2 h with a 100% conversion yield and productivity of 15 mM h−1. We achieved a high productivity of isoquercitrin from rutin. Moreover, these results suggest that α-l-rhamnosidase from C. aurantiacus is an effective isoquercitrin producer.

To increase the production of 10S-hydroxy-8(E)-octadecenoic acid from oleic acid by whole recombinant Escherichia coli cells expressing Nostoc punctiforme 10S-dioxygenase with the aid of a chaperone. The optimal conditions for 10S-hydroxy-8(E)-octadecenoic acid production by recombinant cells co-expressing chaperone plasmid were pH 9, 35 °C, 15 % (v/v) dimethyl sulfoxide, 40 g cells l−1, and 10 g oleic acid l−1. Under these conditions, recombinant cells co-expressing chaperone plasmid produced 7.2 g 10S-hydroxy-8(E)-octadecenoic acid l−1 within 30 min, with a conversion yield of 72 % (w/w) and a volumetric productivity of 14.4 g l−1 h−1. The activity of recombinant cells expressing 10S-dioxygenase was increased by 200 % with the aid of a chaperone, demonstrating the first biotechnological production of 10S-hydroxy-8(E)-octadecenoic acid using recombinant cells expressing 10S-dioxygenase.

To improve the production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid (HODA) from α-linolenic acid in Stenotrophomonas nitritireducens. Cells of the bacterium were permeabilized with 1.25% (v/v) methanol. The optimal conditions for HODA production by permeabilized cells were pH 7, 35 °C, 5% (v/v) DMSO, 50 g cells l−1, and 22.5 g α-linolenic acid l−1. Under these conditions, permeabilized cells produced 16.4 g HODA l−1 after 2 h, with a conversion yield of 73 % (w/w) and a volumetric productivity of 8.2 g l−1 h−1. These values were 153 and 230 % of the values for non-permeabilized cells This is the highest concentration and volumetric and specific productivities of HODA reported thus far.

To characterize l-rhamnose isomerase (l-RI) from the thermophilic bacterium Clostridium stercorarium and apply it to produce d-allose from d-allulose. A recombinant l-RI from C. stercorarium exhibited the highest specific activity and catalytic efficiency (k cat/K m) for l-rhamnose among the reported l-RIs. The l-RI was applied to the high-level production of d-allose from d-allulose. The isomerization activity for d-allulose was maximal at pH 7, 75 °C, and 1 mM Mn2+ over 10 min reaction time. The half-lives of the l-RI at 65, 70, 75, and 80 °C were 22.8, 9.5, 1.9, and 0.2 h, respectively. To ensure full stability during 2.5 h incubation, the optimal temperature was set at 70 °C. Under the optimized conditions of pH 7, 70 °C, 1 mM Mn2+, 27 U l-RI l−1, and 600 g d-allulose l−1, l-RI from C. stercorarium produced 199 g d-allose l−1 without by-products over 2.5 h, with a conversion yield of 33% and a productivity of 79.6 g l−1 h−1. To the best of our knowledge, this is the highest concentration and productivity of d-allose reported thus far.

The optimal conditions for the production of 5,8-dihydroxy-9(Z)-octadecenoic acid (5,8-diHOME) from oleic acid by whole recombinant Escherichia coli cells expressing diol synthase from Aspergillus nidulans were 40 °C, pH 7.5, 10 % (v/v) dimethyl sulfoxide, 35 g cells l(-1), and 12 g oleic acid l(-1) at 250 rpm in a 250 ml baffled flask. Under these conditions, whole recombinant cells produced 5.2 g 5,8-diHOME l(-1) together with 1 g l(-1) of the intermediate 8-hydroperoxy-9(Z)-octadecenoic acid (8-HPOME) after 60 min. This corresponded to a conversion yield of 43 % (w/w), a volumetric productivity of 5.2 g l(-1 )h(-1), and a specific productivity of 148 mg g cells(-1 )h(-1). This is the first report of the biotechnological production of 5,8-diHOME from oleic acid.

β-Glucosidase from Thermus thermophilus has specific hydrolytic activity for the outer glucose at the C-20 position in protopanaxadiol-type ginsenosides without hydrolysis of the inner glucose. The hydrolytic activity of the enzyme for gypenoside XVII was optimal at pH 6.5 and 90 °C, with a half-life of 1 h with 3 g enzyme l(-1) and 4 g gypenoside XVII l(-1). Under the optimized conditions, the enzyme converted the substrate gypenoside XVII to ginsenoside F2 with a molar yield of 100 % and a productivity of 4 g l(-1) h(-1). The conversion yield and productivity of ginsenoside F2 are the highest reported thus far among enzymatic transformations.

To produce δ-decalactone from linoleic acid by one-pot reaction using linoleate 13-hydratase with supplementation with whole Yarrowia lipolytica cells.Whole Y. lipolytica cells at 25 g l(-1) produced1.9 g l(-1) δ-decalactone from 7.5 g 13-hydroxy-9(Z)-octadecenoic acid l(-1) at pH 7.5 and 30 °C for 21 h. Linoleate 13-hydratase from Lactobacillus acidophilus at 3.5 g l(-1) with supplementation with 25 g Y. lipolytica cells l(-1) in one pot at 3 h produced 1.9 g l(-1) δ-decalactone from 10 g linoleic acid l(-1) via 13-hydroxy-9(Z)-octadecenoic acid intermediate at pH 7.5 and 30°C after 18 h, with a molar conversion yield of 31 % and productivity of 106 mg l(-1) h(-1).To the best of our knowledge, this is the first production of δ-decalactone using unsaturated fatty acid.