Subcritical Water as a Pre-Treatment of Mixed Microbial Biomass for the Extraction of Polyhydroxyalkanoates.

Polyhydroxyalkanoate (PHA) recovery from microbial cells relies on either solvent extraction (usually using halogenated solvents) and/or digestion of the non-PHA cell mass (NPCM) by the action of chemicals (e.g., hypochlorite) that raise environmental and health hazards.

White wine grape pomace as a suitable carbon source for lipid and carotenoid production by fructophilic Rhodorotula babjevae.

Aim: We aim to explore the non-structural sugars from white wine grape pomace (WWGP) as the input carbon source for the co-production of multiple high-value products by the non-fastidious yeast Rhodotorula babjevae to create a sustainable and economically appealing process.

Methods And Results: Water extraction of unfermented, soluble sugars from WWGP yielded extracts with similar amounts of glucose and fructose, which were used to prepare a growth medium. Rhodorotula babjevae multiplied as fast on WWGP-based medium as on a reference medium but achieved higher cell dry weight (CDW) and lower intracellular triacylglycerol accumulation (22.

Valorization of Cork Using Subcritical Water.

Granulated cork was submitted to subcritical water extraction/hydrolysis in a semi-continuous reactor at temperatures in the range of 120-200 °C and with a constant pressure of 100 bar. The influence of temperature on the composition of the cork extracts obtained was assessed-namely, their content of carbohydrates and phenolics. The extraction yield increased with the temperature, and this was associated with the decrease in the dielectric constant of water and the increase in its ionic product.

Solubility of Polar and Nonpolar Aromatic Molecules in Subcritical Water: The Role of the Dielectric Constant.

Liquid water at temperatures above the boiling point and high pressures, also known as pressurized hot water, or subcritical water (SBCW), is an effective solvent for both polar and nonpolar organic solutes. This is often associated with the decrease of water's dielectric constant at high temperatures, apparently allowing water to behave like an organic solvent. The decrease of the solubility at high pressures, in turn, is explained by a mild increase of the dielectric constant of water.

Stabilizing Unstable Amorphous Menthol through Inclusion in Mesoporous Silica Hosts.

The amorphization of the readily crystallizable therapeutic ingredient and food additive, menthol, was successfully achieved by inclusion of neat menthol in mesoporous silica matrixes of 3.2 and 5.9 nm size pores.

Production of Electrospun Fast-Dissolving Drug Delivery Systems with Therapeutic Eutectic Systems Encapsulated in Gelatin.

Fast-dissolving delivery systems (FDDS) have received increasing attention in the last years. Oral drug delivery is still the preferred route for the administration of pharmaceutical ingredients. Nevertheless, some patients, e.

A comparison between pure active pharmaceutical ingredients and therapeutic deep eutectic solvents: Solubility and permeability studies.

THEDES, so called therapeutic deep eutectic solvents are here defined as a mixture of two components, which at a particular molar composition become liquid at room temperature and in which one of them is an active pharmaceutical ingredient (API). In this work, THEDES based on menthol complexed with three different APIs, ibuprofen (ibu), BA (BA) and phenylacetic acid (PA), were prepared. The interactions between the components that constitute the THEDES were studied by NMR, confirming that the eutectic system is formed by H-bonds between menthol and the API.

Probing sol-gel matrices microenvironments by PGSE HR-MAS NMR.

We applied Pulsed Gradient Spin Echo diffusion with high-resolution magic angle spinning NMR to study sol-gel matrices used to encapsulate enzymes for biocatalysis (TMOS/MTMS and TMOS/BTMS) to gain insight into the local chemical microenvironment. Transport properties of solvents with different polarities (1-pentanol, acetonitrile and n-hexane) were studied through their apparent self-diffusion coefficients. The spin echo attenuation of the solvents shows two distinct diffusion domains, one with fast diffusion (D ) associated with interparticle diffusion and another with slow diffusion (D ) corresponding to the displacement inside the pores within the sol-gel particles.

Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systems.

A therapeutic deep eutectic system (THEDES) is here defined as a deep eutectic solvent (DES) having an active pharmaceutical ingredient (API) as one of the components. In this work, THEDESs are proposed as enhanced transporters and delivery vehicles for bioactive molecules. THEDESs based on choline chloride (ChCl) or menthol conjugated with three different APIs, namely acetylsalicylic acid (AA), benzoic acid (BA) and phenylacetic acid (PA), were synthesized and characterized for thermal behaviour, structural features, dissolution rate and antibacterial activity.

Design of controlled release systems for THEDES-Therapeutic deep eutectic solvents, using supercritical fluid technology.

Deep eutectic solvents (DES) can be formed by bioactive compounds or pharmaceutical ingredients. A therapeutic DES (THEDES) based on ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), and menthol was synthesized and its thermal behavior was analyzed by differential scanning calorimetry (DSC). A controlled drug delivery system was developed by impregnating a starch:poly-ϵ-caprolactone polymeric blend (SPCL 30:70) with the menthol:ibuprofen THEDES in different ratios (10 and 20 wt%), after supercritical fluid sintering at 20 MPa and 50 °C.

Ion jelly conductive properties using dicyanamide-based ionic liquids.

The thermal behavior and transport properties of several ion jellys (IJs), a composite that results from the combination of gelatin with an ionic liquid (IL), were investigated by dielectric relaxation spectroscopy (DRS), differential scanning calorimetry (DSC), and pulsed field gradient nuclear magnetic resonance spectroscopy (PFG NMR). Four different ILs containing the dicyanamide anion were used: 1-butyl-3-methylimidazolium dicyanamide (BMIMDCA), 1-ethyl-3-methylimidazolium dicyanamide (EMIMDCA), 1-butyl-1-methylpyrrolidinium dicyanamide (BMPyrDCA), and 1-butylpyridinium dicyanamide (BPyDCA); the bulk ILs were also investigated for comparison. A glass transition was detected by DSC for all materials, ILs and IJs, allowing them to be classified as glass formers.

Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology.

Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.

Ion jelly: a tailor-made conducting material for smart electrochemical devices.

We present a new concept for the design of a polymeric conducting material that combines the chemical versatility of an organic salt (ionic liquid) with the morphological versatility of a biopolymer (gelatin); the resulting 'ion jelly' can be applied in electrochemical devices, such as batteries, fuel cells, electrochromic windows or photovoltaic cells.

Probing the microenvironment of sol-gel entrapped cutinase: the role of added zeolite NaY.

Cutinase, an esterase from Fusarium solani pisi, was immobilized in sol-gel matrices of composition 1:5 tetramethoxysilane (TMOS):n-alkyltrimethoxysilane (n-alkylTMS). Fluorescence spectroscopy using the single tryptophan (Trp-69) residue of cutinase as a probe revealed that the polarity of the matrices decreased as their hydrophobicity increased up to the TMOS/n-butylTMS pair, which correlates with an increase in cutinase activity. Fluorescence emission was suppressed (a higher than two orders of magnitude reduction) in the TMOS/n-octylTMS matrix, suggesting a greater proximity of the tryptophan to a nearby disulfide bridge.

Sol-gel encapsulation: an efficient and versatile immobilization technique for cutinase in non-aqueous media.

Cutinase from Fusarium solani pisi was encapsulated in sol-gel matrices prepared with a combination of alkyl-alkoxysilane precursors of different chain-lengths. The specific activity of cutinase in a model transesterification reaction at fixed water activity in n-hexane was highest for the precursor combination tetramethoxysilane/n-butyltrimetoxysilane (TMOS/BTMS) in a 1:5 ratio, lower and higher chain lengths of the mono-alkylated precursor or decreasing proportions of the latter relative to TMOS leading to lower enzyme activity. Results obtained using combinations of three precursors confirmed the beneficial effect of the presence of BTMS in the preparations.

Effect of immobilization support, water activity, and enzyme ionization state on cutinase activity and enantioselectivity in organic media.

We studied the reaction between vinyl butyrate and 2-phenyl-1-propanol in acetonitrile catalyzed by Fusarium solani pisi cutinase immobilized on zeolites NaA and NaY and on Accurel PA-6. The choice of 2-phenyl-1-propanol was based on modeling studies that suggested moderate cutinase enantioselectivity towards this substrate. With all the supports, initial rates of transesterification were higher at a water activity (a(w)) of 0.

Salt hydrates for in situ water activity control have acid-base effects on enzymes in nonaqueous media.

Salt hydrates very frequently are utilized as in situ water activity buffers in reaction mixtures of enzymes in nonaqueous media. In addition to buffering water activity, there is evidence that salt hydrates also often affect initial rates in other ways. This has been generally overlooked or thought to be related to water transfer effects.

Water activity effects on geranyl acetate synthesis catalyzed by novozym in supercritical ethane and in supercritical carbon dioxide.

The esterification reaction of geraniol with acetic acid catalyzed by Novozym was studied in supercritical ethane (sc-ethane) and in supercritical carbon dioxide (sc-CO(2)). Water activity (a(W)) had a very strong effect on enzyme activity, with reaction rates increasing up to a(W) = 0.25 and then decreasing for higher a(W).

Enhancement of enzyme activity in supercritical carbon dioxide via changes in acid-base conditions.

Enzyme performance is often impaired in supercritical carbon dioxide. We were able to enhance enzyme activity in this medium via changes in acid-base conditions by using ion-exchange materials (solid H(+)/Na(+) buffer pairs and a zeolite), which were selected on the basis of the response of an organosoluble acid-base indicator. The concentration of ion-exchange materials had an important effect on the catalytic activity of subtilisin Carlsberg cross-linked enzyme crystals (CLECs), and this was related to the protonation and hydration states of the enzyme.

Zeolite molecular sieves have dramatic acid-base effects on enzymes in nonaqueous media.

Zeolite molecular sieves very commonly are used as in situ drying agents in reaction mixtures of enzymes in nonaqueous media. They often affect enzyme behavior, and this has been interpreted in terms of altered hydration. Here, we show that zeolites can also have dramatic acid-base effects on enzymes in low water media, resulting from their cation-exchange ability.