Production of 10(S)-hydroxy-8(E)-octadecenoic acid mono-estolides by lipases in non-aqueous media

Synthesis, characterization and enzymatic degradation of copolymers of ε-caprolactone and hydroxy-fatty acids

New copolymers of ε-caprolactone with three hydroxy-fatty acids, 12-hydroxy stearic acid, 16-hydroxyhexadecanoic acid and ricinoleic acid, were synthesized by catalytic polyesterification. The reactions were carried out in solvent-free systems and in organic solvents as well, using tin(II) 2-ethylhexanoate as catalyst, at different temperatures and molar ratios of the comonomers. Cyclic and linear polymeric products with medium molar weight of about 2000 Da have been synthesized and their chemical structures were confirmed by FT-IR, NMR and MALDI-TOF MS analysis. The synthesis parameters were optimized and the ε-caprolactone/hydroxy acid molar ratio was set as 5:1, according to mass spectrometry results. The biodegradability of the newly synthesized polymers was studied in the presence of Candida antarctica B lipase in phosphate buffer solutions (pH=7.4), at 37°C. The weight-loss profile emphasized the degradation of the 16-hydroxyhexadecanoic acid based polymer samples at more than 50% of their initial weight in 18 days of incubation in the presence of the lipase. The composition of the degradation products was assessed using the GC-MS technique and displayed residues of the comonomers moieties.

Production of 10R-hydroxy unsaturated fatty acids from hempseed oil hydrolyzate by recombinant Escherichia coli cells expressing PpoC from Aspergillus nidulans

The first and second preferred substrates of recombinant Escherichia coli cells expressing 10R-dioxygenase (PpoC) from Aspergillus nidulans and the purified enzyme were linoleic acid and α-linolenic acid, respectively. PpoC in cells showed higher thermal and reaction stabilities compared to purified PpoC. Thus, 10R-hydroxy unsaturated fatty acids were produced from linoleic acid, α-linolenic acid, and hempseed oil hydrolyzate containing linoleic acid and α-linolenic acid as substrates by whole recombinant cells expressing PpoC. The optimal reaction conditions for the production of 10R-hydroxy-8E,12Z-octadecadienoic acid (10R-HODE) were pH 8.0, 30 °C, 250 rpm, 5 % (v/v) dimethyl sulfoxide, 5 g l(-1) linoleic acid, and 60 g l(-1) cells in 100-ml baffled flask. Under these conditions, whole recombinant cells expressing PpoC produced 2.7 g l(-1) 10R-HODE from 5 g l(-1) linoleic acid for 40 min, with a conversion yield of 54 % (w/w) and a productivity of 4.0 g l(-1) h(-1); produced 2.2 g l(-1) 10R-hydroxy-8E,12Z,15Z-octadecatrienoic acid (10R-HOTrE) from 3 g l(-1) α-linolenic acid for 30 min, with a conversion yield of 72 % (w/w) and a productivity of 4.3 g l(-1) h(-1); and produced 1.8 g l(-1) 10R-HODE and 0.5 g l(-1) 10R-HOTrE from 5 g l(-1) hempseed oil hydrolyzate containing 2.5 g l(-1) linoleic acid and 1.0 g l(-1) α-linolenic acid for 30 min, with a conversion yield of 74 and 51 % (w/w), respectively, and a productivity of 3.6 and 1.0 g l(-1) h(-1), respectively. To the best of our knowledge, this is the first report on the biotechnological production of 10R-hydroxy unsaturated fatty acids.

Selectivity of lipases for estolides synthesis

Lipase-catalyzed synthesis of estolides starting from different saturated (C16 16OH, C18 12OH) and unsaturated (C18:1 9 cis 12-OH) hydroxy-fatty acids was investigated. For this reason, the catalytic efficiency of several native and immobilized lipases in different organic reaction media at temperatures up to 75 °C was studied. The formation of mono- and di-lactone as well as estolide’s chain elongation depends on the type and source of lipase. The lipase from Pseudomonas stutzeri immobilized by cross-linking as cross-linked enzymes aggregates (CLEAs) was the best biocatalyst in terms of chain elongation. Estolides with polymerization degree up to 10 were obtained at substrate conversions higher than 80 %.

Yield and kinetic constants estimation in the production of hydroxy fatty acids from oleic acid in a bioreactor by Pseudomonas aeruginosa 42A2

We modelled the production of hydroxy fatty acids from oleic acid by Pseudomonas aeruginosa 42A2 in a bioreactor with a non-dispersive aeration system. First, we designed an adapted wetted-wall gas-absorption column, offering a k La value of 39.9 h(-1), to enhance oxygen absorption in the culture media and prevent foam formation. Then, we analysed different kinetic models to simulate the yield coefficients and the kinetic constants in this bacterial transformation. Monod model fitting (μ max1 = 0.51 h(-1), K S1 = 1.60 C-mol l(-1), μ max2 = 0.12 h(-1), K S2 = 0.035 C-mol l(-1), and k 2 = 0.033 h(-1)) showed a good accuracy with the experimental data sets and was chosen for its simplicity. Lastly, mass balances were carried out to establish the stoichiometry of this biotransformation with the following yield coefficients, Υ X/OA, Υ X/(10S)-HPOME and Υ (10S)-HPOME/(7S10S)-HPOME of 0.172, 0.347 and 2.388 C-mol C-mol(-1), respectively.

Production of 10(S)-hydroxy-8(E)-octadecenoic and 7,10(S,S)-hydroxy-8(E)-octadecenoic ethyl esters by Novozym 435 in solvent-free media

Novozym 435, lipase B from Candida antarctica, was used in this study for the production of ethyl esters. For the first time, trans-hydroxy-fatty acid ethyl esters were synthesized in vitro in solvent-free media. We studied the effects of the substrate-ethanol molar ratio and enzyme synthetic stability of the biocatalyst. To determine the structure of the formed compounds, Fourier transformed infrared spectroscopy, nuclear magnetic resonance, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry were used, three less time-consuming structural techniques. trans-Hydroxy-fatty acid ethyl esters were synthesized with a reaction yield of 90 % or higher with optimal reaction conditions.