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1.
Recombinant Escherichia coli, expressing the oleate hydratase gene of Stenotrophomonas maltophilia, was permeabilized by sequential treatments with 0.125 M NaCl and 2 mM EDTA. The optimal conditions for the production of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid from α-linolenic acid by permeabilized cells were 35 °C and pH 7.0 with 0.1 % (v/v) Tween 40, 50 g permeabilized cells l?1, and 17.5 g α-linolenic acid l?1. Under these conditions, permeabilized cells produced 14.3 g 10-hydroxy-12,15(Z,Z)-octadecadienoic acid l?1 after 18 h, with a conversion yield of 82 % (g/g) and a volumetric productivity of 0.79 g l?1 h?1. These values were 17 and 168 % higher than those obtained by nonpermeabilized cells, respectively. The concentration, yield, and productivity of 10-hydroxy-12,15(Z,Z)-octadecadienoic acid obtained by permeabilized cells are the highest reported thus far.  相似文献   

2.
Diol synthase-derived metabolites are involved in the sexual and asexual life cycles of fungi. A putative diol synthase from Penicillium oxalicum was found to convert palmitoleic acid (16:1n-7), oleic acid (18:1n-9), linoleic acid (18:2n-6), and α-linolenic acid (18:3n-3) to 6S,8R-dihydroxy-9(Z)-hexadecenoic acid, 6R,8R-dihydroxy-9(Z)-octadecenoic acid, 6R,8R-dihydroxy-9,12(Z,Z)-octadecadienoic acid, and 6S,8R-dihydroxy-9,12,15(Z,Z,Z)-octadecatrienoic acid, respectively, which were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and nuclear magnetic resonance (NMR) spectroscopy analyses. The specific activity and catalytic efficiency of P. oxalicum 6,8-diol synthase were the highest for 18:2n-6, indicating that the enzyme is a 6R,8R-linoleate diol synthase (6R,8R-LDS) with new regiospecificity. This is the first report of a 6R,8R-LDS. LDS is a fusion protein consisting of a dioxygenase domain at the N-terminus and a cytochrome P450/hydroperoxide isomerase (P450/HPI) domain at the C-terminus. The putative active-site residues in the C-terminal domain of P. oxalicum 6R,8R-LDS were proposed based on a substrate-docking homology model. The results of the site-directed mutagenesis within C-terminal P450 domain suggested that Asn886, Arg707, and Arg934, are catalytic importance and belong to the catalytic groove. Phe794 and Gln889 were found to be involved in the regiospecific rearrangement of hydroperoxide, while the F794E and Q889A variants of P. oxalicum 6,8-LDS acted as 7,8- and 8,11-LDSs, respectively. All these mutations critically affected the HPI activity of P. oxalicum 6R,8R-LDS.  相似文献   

3.
Oxygenation of linoleic acid by Aspergillus terreus was studied with LC-MS/MS. 9(R)-Hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HpODE) was identified along with 10(R)-hydroxy-8(E),12(Z)-octadecadienoic acid and variable amounts of 8(R)-hydroxy-9(Z),12(Z)-octadecadienoic acid. 9R-HpODE was formed from [11S-2H]18:2n − 6 with loss of the deuterium label, suggesting antarafacial hydrogen abstraction and oxygenation. Two polar metabolites were identified as 9-hydroxy-10-oxo-12(Z)-octadecenoic acid (α-ketol) and 13-hydroxy-10-oxo-11(E)-octadecenoic acid (γ-ketol), likely formed by spontaneous hydrolysis of an unstable allene oxide, 9(R),10-epoxy-10,12(Z)-octadecadienoic acid. α-Linolenic acid and 20:2n − 6 were oxidized to hydroperoxy fatty acids at C-9 and C-11, respectively, but α- and γ-ketols of these fatty acids could not be detected. The genome of A. terreus lacks lipoxygenases, but contains genes homologous to 5,8-linoleate diol synthases and linoleate 10R-dioxygenases of aspergilli. Our results demonstrate that linoleate 9R-dioxygenase linked to allene oxide synthase activities can be expressed in fungi.  相似文献   

4.
Allylic hydroxylated derivatives of the C18 unsaturated fatty acids were prepared from linoleic acid (LA) and conjugated linoleic acids (CLAs). The reaction of LA methyl ester with selenium dioxide (SeO2) gave mono-hydroxylated derivatives, 13-hydroxy-9Z,11E-octadecadienoic acid, 13-hydroxy-9E,11E-octadecadienoic acid, 9-hydroxy-10E,12Z-octadecadienoic acid and 9-hydroxy-10E,12E-octadecadienoic acid methyl esters. In contrast, the reaction of CLA methyl ester with SeO2 gave di-hydroxylated derivatives as novel products including, erythro-12,13-dihydroxy-10E-octadecenoic acid, erythro-11,12-dihydroxy-9E-octadecenoic acid, erythro-10,11-dihydroxy-12E-octadecenoic acid and erythro-9,10-dihydroxy-11E-octadecenoic acid methyl esters. These products were purified by normal-phase short column vacuum chromatography followed by high-performance liquid chromatography (HPLC). Their chemical structures were characterized by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR). The allylic hydroxylated derivatives of LA and CLA exhibited moderate in vitro cytotoxicity against a panel of human cancer cell lines including chronic myelogenous leukemia K562, myeloma RPMI8226, hepatocellular carcinoma HepG2 and breast adenocarcinoma MCF-7 cells (IC50 10-75 μM). The allylic hydroxylated derivatives of LA and CLA also showed toxicity to brine shrimp with LD50 values in the range of 2.30-13.8 μM. However these compounds showed insignificant toxicity to honeybee at doses up to 100 μg/bee.  相似文献   

5.
Hydroxy unsaturated fatty acids can be used as antimicrobial surfactants. 8,11‐Linoleate diol synthase (8,11‐LDS) catalyzes the conversion of unsaturated fatty acid to 8‐hydroperoxy unsaturated fatty acid, and it is subsequently isomerized to 8,11‐dihydroxy unsaturated fatty acid by the enzyme. The optimal reaction conditions of recombinant Escherichia coli expressing Penicillium chrysogenum 8,11‐LDS for the production of 8,11‐dihydroxy‐9,12(Z,Z)‐octadecadienoic acid (8,11‐DiHODE), 8,11‐dihydroxy‐9,12,15(Z,Z,Z)‐octadecatrienoic acid (8,11‐DiHOTrE), 8‐hydroxy‐9(Z)‐hexadecenoic acid (8‐HHME), and 8‐hydroxy‐9(Z)‐octadecenoic acid (8‐HOME) were pH 7.0, 25°C, 10 g/L linoleic acid, and 20 g/L cells; pH 6.0, 25°C, 6 g/L α‐linolenic acid, and 60 g/L cells; pH 7.0, 25°C, 8 g/L palmitoleic acid, and 25 g/L cells; and pH 8.5, 30°C, 6 g/L oleic acid, and 25 g/L cells, respectively. Under these optimized conditions, the recombinant cells produced 6.0 g/L 8,11‐DiHODE for 60 min, with a conversion of 60% (w/w) and a productivity of 6.0 g/L/h; 4.3 g/L 8,11‐DiHOTrE for 60 min, with a conversion of 72% (w/w) and a productivity of 4.3 g/L/h; 4.3 g/L 8‐HHME acid for 60 min, with a conversion of 54% (w/w) and a productivity of 4.3 g/L/h; and 0.9 g/L 8‐HOME for 30 min, with a conversion of 15% (w/w) and a productivity of 1.8 g/L/h. To best of our knowledge, this is the first report on the biotechnological production of 8,11‐DiHODE, 8,11‐DiHOTrE, 8‐HHME, and 8‐HOME. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:390–396, 2017  相似文献   

6.
Aspergilli express fusion proteins of an animal haem peroxidase domain with fatty acid dioxygenase (DOX) activity (∼ 600 amino acids) and a functional or non-functional hydroperoxide isomerase/cytochrome P450 domain (∼ 500 amino acids with EXXR and GPHXCLG motifs). 5,8-Linoleate diol synthases (LDS; ppoA) and 10R-DOX (ppoC) of Aspergillusnidulans and A. fumigatus belong to this group. Our objective was to determine the oxylipins formed from linoleic acid by A. clavatus and their mechanism of biosynthesis. A. clavatus oxidized linoleic acid to (8R)-hydroperoxylinoleic acid (8R-HPODE), (10R)-hydroperoxy-8(E),12(Z)-octadecadienoic acid (10R-HPODE), and to (5S,8R)-dihydroxy- and (8R,11S)-dihydroxylinoleic acids (DiHODE) as major products. This occurred by abstraction of the pro-S hydrogen at C-8 and antarafacial dioxygenation at C-8 or at C-10 with double bond migration. 8R-HPODE was then isomerized to 5S,8R-DiHODE and to 8R,11S-DiHODE by abstraction of the pro-S hydrogens at C-5 and C-11 of 8R-HPODE, respectively, followed by suprafacial oxygenation. The genome of A. clavatus codes for two enzymes, which can be aligned with > 65% amino acid identity to 10R-DOX and 5,8-LDS, respectively. The 5,8-LDS homologue likely forms and isomerizes 8R-HPODE to 5S,8R-DiHODE. A third gene (ppoB) codes for a protein which carries a serine residue at the cysteine position of the P450 motif. This Cys to Ser replacement is known to abolish P450 2B4 catalysis and the hydroperoxide isomerase activity of 5,8-LDS, suggesting that ppoB of A. clavatus may not be involved in the biosynthesis of 8R,11S-DiHODE.  相似文献   

7.
The fatty acid compositions of 10 types of tree oils were analyzed and Camellia japonica (CJ), Tetradium daniellii (TD), and Hovenia dulcis (HD) tree oils were selected to be oleic acid (OA)-, linoleic acid (LA)-, and α-linoleic acid (ALA)-rich tree oils, respectively. Recombinant Escherichia coli expressing 10-hydratase and 7,8-diol synthase converted 31.7 and 15.6 g/L unsaturated fatty acids (UFAs) in OA-rich oil hydrolysates to 21.7 g/L 10-monohydroxy fatty acid (monoHFA) and 13.3 g/L 7,8-diHFA, respectively. The cells expressing 13-hydratase, 13-lipoxygenase, 5,8-diol synthase, and 8,11-diol synthase converted 42.8, 28.5, 10.0, and 20.0 g/L UFAs in LA-rich oil hydrolysates to 28.2 g/L 13-monoHFA, 11.8 g/L 13-monoHFA, 7.2 g/L 5,8-diHFA, and 8.9 g/L 8,11-diHFA, respectively. The cells expressing 8,11-diol synthase converted containing 17.5 g/L UFAs in ALA-rich oil hydrolysate to 7.5 g/L 8,11-diHFA. The average emulsifying activities of diHFArich and monoHFA-rich tree oil hydrolysates were 13.9- and 4.3-fold higher than those of tree oil hydrolysates, respectively. Thus, HFA-rich tree oil hydrolysates derived from tree oils can be applied as biosurfactants, and the fatty acid-rich residue as by-product obtained from the tree refinery process may be recycled into biosurfactants.  相似文献   

8.
A recombinant oleate hydratase from Lysinibacillus fusiformis converted ricinoleic acid to a product, whose chemical structure was identified as the novel compound 10,12-dihydroxystearic acid by gas chromatograph/mass spectrometry, Fourier transform infrared, and nuclear magnetic resonance analysis. The reaction conditions for the production of 10,12-dihydroxystearic acid were optimized as follows: pH?6.5, 30 °C, 15 g?l?1 ricinoleic acid, 9 mg?ml?1 of enzyme, and 4 % (v/v) methanol. Under the optimized conditions, the enzyme produced 13.5 g?l?1 10,12-dihydroxystearic acid without detectable byproducts in 3 h, with a conversion of substrate to product of 90 % (w/w) and a productivity of 4.5 g?l?1?h?1. The emulsifying activity of 10,12-dihydroxystearic acid was higher than that of oleic acid, ricinoleic acid, stearic acid, and 10-hydroxystearic acid, indicating that 10,12-dihydroxystearic acid can be used as a biosurfactant.  相似文献   

9.
Escherichia coli W, a sucrose-positive strain, was engineered for the homofermentative production of d-lactic acid through chromosomal deletion of the competing fermentative pathway genes (adhE, frdABCD, pta, pflB, aldA) and the repressor gene (cscR) of the sucrose operon, and metabolic evolution for improved anaerobic cell growth. The resulting strain, HBUT-D, efficiently fermented 100?g?sucrose?l?1 into 85?g?d-lactic acid?l?1 in 72–84?h in mineral salts medium with a volumetric productivity of ~1?g?l?1?h?1, a product yield of 85?% and d-lactic acid optical purity of 98.3?%, and with a minor by-product of 4?g?acetate?l?1. HBUT-D thus has great potential for production of d-lactic acid using an inexpensive substrate, such as sugar cane and/or beet molasses, which are primarily composed of sucrose.  相似文献   

10.
Isomaltulose is a structural isomer of sucrose commercially used in food industries. In this work, recombinant Escherichia coli producing sucrose isomerase (SIase) was used to convert sucrose into isomaltulose. To develop an economical industrial medium, untreated cane molasses (10.63 g l?1), yeast extract (25.93 g l?1), and corn steep liquor (10.45 g l?1) were used as main culture compositions for SIase production. The relatively high SIase activity (14.50 ± 0.11 U mg DCW?1) was obtained by the recombinant cells. To the best of our knowledge, this is the first investigation on SIase production by engineered E. coli using untreated cane molasses. The recombinant E. coli cells expressing the SIase gene were immobilized in calcium alginate gel in order to improve the efficiency of recycling. The immobilization was most effective with 2 % (w/v) sodium alginate and 3 % (w/v) calcium chloride. The optimal initial biomass for immobilization was 20 % (w/v, wet wt.), with a hardening time of 8 h for cell immobilization. The immobilized E. coli cells exhibited good stability for 30 batches with the productivity of 0.45 g isomaltulose g pellet?1 h?1. A continuous isomaltulose formation process using a column reactor remained stable for 40 days with 83 ± 2 % isomaltulose yield, which would be beneficial for economical production of isomaltulose.  相似文献   

11.

Objective

To produce δ-decalactone from linoleic acid by one-pot reaction using linoleate 13-hydratase with supplementation with whole Yarrowia lipolytica cells.

Results

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.

Conclusion

To the best of our knowledge, this is the first production of δ-decalactone using unsaturated fatty acid.
  相似文献   

12.
The nitrilase gene of Rhodococcus rhodochrous J1 was expressed in Escherichia coli using the expression vector, pKK223-3. The recombinant E. coli JM109 cells hydrolyzed enantioselectively 2-methyl-2-propylmalononitrile to form (S)-2-cyano-2-methylpentanoic acid (CMPA) with 96 % e.e. Under optimized conditions, 80 g (S)-CMPA l?1 was produced with a molar yield of 97 % at 30 °C after a 24 h without any by-products.  相似文献   

13.

Objective

To improve the production of trans-10,cis-12-conjugated linoleic acid (t10,c12-CLA) from linoleic acid in recombinant Yarrowia lipolytica.

Results

Cells of the yeast were permeabilized by freeze/thawing. The optimal conditions for t10,c12-CLA production by the permeabilized cells were at 28 °C, pH 7, 200 rpm with 1.5 g sodium acetate l?1, 100 g wet cells l?1, and 25 g LA l?1. Under these conditions, the permeabilized cells produced 15.6 g t10,c12-CLA l?1 after 40 h, with a conversion yield of 62 %. The permeabilized cells could be used repeatedly for three cycles, with the t10,c12-CLA extracellular production remaining above 10 g l?1.

Conclusion

Synthesis of t10,c12-CLA was achieved using a novel method, and the production reported in this work is the highest value reported to date.
  相似文献   

14.
N-acetylneuraminic acid (NeuAc) has recently drawn much attention owing to its wide applications in many aspects. Besides extraction from natural materials, production of NeuAc was recently focused on enzymatic synthesis and whole-cell biocatalysis. In this study, we designed an artificial NeuAc biosynthetic pathway through intermediate N-acetylglucosamine 6-phosphate in Escherichia coli. In this pathway, N-acetylglucosamine 2-epimerase (slr1975) and glucosamine-6-phosphate acetyltransferase (GNA1) were heterologously introduced into E. coli from Synechocystis sp. PCC6803 and Saccharomyces cerevisiae EBY100, respectively. By derepressing the feedback inhibition of glucosamine-6-phosphate synthase, increasing the accumulation of N-acetylglucosamine and pyruvate, and blocking the catabolism of NeuAc, we were able to produce 1.62 g l?1 NeuAc in recombinant E. coli directly from glucose. The NeuAc yield reached 7.85 g l?1 in fed-batch fermentation. This process offered an efficient fermentative method to produce NeuAc in microorganisms using glucose as carbon source and can be optimized for further improvement.  相似文献   

15.
Linoleic acid was transformed by mutant Candida tropicalis M25 and transformations were studied in batch and fed-batch cultures. Cofermentations with palmitic acid as inducer of the fatty acid degradation pathway were performed. Besides the (Z),(Z)-octadeca-6,9-dienedioic acid, (Z),(Z)-3-hydroxyoctadeca-9,12-dienedioic acid and (Z),(Z)-3-hydroxytetradeca-5,8-dienedioic acid were obtained as the main fermentation products. The maximum concentrations of (Z),(Z)-octadeca-6,9-dienedioic acid and (Z),(Z)-3-hydroxyoctadeca-9,12-dienedioic acid reached values of 6.4 g/l and 6.9 g/l respectively. The structures of the products were characterized by chemical and spectroscopic methods. The configuration of the double bonds was not changed during bioconversion. As only one regioisomer of the hydroxylated fatty acid was detected, the hydroxylation is site-specific. Received: 11 November 1996 / Received revision: 11 February 1997 / Accepted: 24 February 1997  相似文献   

16.
The rhizocticines and plumbemicines are two groups of di- and tripeptid antibiotics thought to interfere with threonine or threonine-related metabolism. Z-2-amino-5-phosphono-3-pentenoic acid, the common unusual amino acid constituent of the rhizocticines and plumbemicines, was found to irreversibly inhibit Escherichia coli threonine synthase in a time-dependent reaction that followed pseudo-first order and saturation kinetics. These data provide evidence that the toxicity of the rhizocticines and plumbemicines is due to the inhibition of threonine synthase by Z-2-amino-5-phosphone-3-pentenoic acid, which is liberated by peptidases after uptake into the target cell. Additionally, methods for the purification of threonine synthase from an overproducing E. coli strain and for the enzymatic synthesis of l-homoserine phosphate are described.Abbreviations APPA Z-2-amino-5-phosphono-3-pentenoic acid - HSerP l-homoserine phosphate - PEP phosphoenolpyruvate - PLP pyndoxal 5-phosphate - TS threonine synthase  相似文献   

17.
We report here that Tyrophagus similis and Tyrophagus putrescentiae (Astigmata: Acaridae) have the ability to biosynthesize linoleic acid [(9Z, 12Z)-9, 12-octadecadienoic acid] via a Δ12-desaturation step, although animals in general and vertebrates in particular appear to lack this ability. When the mites were fed on dried yeast enriched with d31-hexadecanoic acid (16:0), d27-octadecadienoic acid (18:2), produced from d31-hexadecanoic acid through elongation and desaturation reactions, was identified as a major fatty acid component of phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) in the mites. The double bond position of d27-octadecadienoic acid (18:2) of PCs and PEs was determined to be 9 and 12, respectively by dimethyldisulfide (DMDS) derivatization. Furthermore, the GC/MS retention time of methyl 9, 12-octadecadienoate obtained from mite extracts agreed well with those of authentic linoleic acid methyl ester. It is still unclear whether the mites themselves or symbiotic microorganisms are responsible for inserting a double bond into the Δ12 position of octadecanoic acid. However, we present here the unique metabolism of fatty acids in the mites.  相似文献   

18.
Hydroperoxide lyase (HPL) cleaves lipid hydroperoxides to produce volatile flavor molecules and also potential signal molecules. We have characterized a gene from Arabidopsis that is homologous to a recently cloned HPL from green pepper (Capsicum annuum). The deduced protein sequence indicates that this gene encodes a cytochrome P-450 with a structure similar to that of allene oxide synthase. The gene was cloned into an expression vector and expressed in Escherichia coli to demonstrate HPL activity. Significant HPL activity was evident when 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid was used as the substrate, whereas activity with 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid was approximately 10-fold lower. Analysis of headspace volatiles by gas chromatography-mass spectrometry, after addition of the substrate to E. coli extracts expressing the protein, confirmed enzyme-activity data, since cis-3-hexenal was produced by the enzymatic activity of the encoded protein, whereas hexanal production was limited. Molecular characterization of this gene indicates that it is expressed at high levels in floral tissue and is wound inducible but, unlike allene oxide synthase, it is not induced by treatment with methyl jasmonate.  相似文献   

19.
Phenolic acid decarboxylase (PAD) catalyzes the non-oxidative decarboxylation of p-coumaric acid (pCA) to p-hydroxystyrene (pHS). PAD from Bacillus amyloliquefaciens (BAPAD), which showed k cat/K m value for pCA (9.3?×?103?mM?1?s?1), was found as the most active one using the “Subgrouping Automata” program and by comparing enzyme activity. However, the production of pHS of recombinant Escherichia coli harboring BAPAD showed only a 22.7 % conversion yield due to product inhibition. Based on the partition coefficient of pHS and biocompatibility of the cell, 1-octanol was selected for the biphasic reaction. The conversion yield increased up to 98.0 % and 0.83 g/h/g DCW productivity was achieved at 100 mM pCA using equal volume of 1-octanol as an organic solvent. In the optimized biphasic reactor, using a three volume ratio of 1-octanol to phosphate buffer phase (50 mM, pH 7.0), the recombinant E. coli produced pHS with a 88.7 % conversion yield and 1.34 g/h/g DCW productivity at 300 mM pCA.  相似文献   

20.
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