Aqueous biphasic systems developed with deep eutectic solvents and polymer for the efficient extraction of pigments from beverages.

Novel aqueous biphasic systems (ABSs) developed with benzyl-based quaternary ammonium salts-deep eutectic solvents (DESs) and polypropylene glycol (PPG) were herein proposed. The liquid-liquid equilibrium and the partitioning behavior of pigments in the systems were addressed. The results suggested that the shorter the carbon chain length of the DES, the easier to form two phases. The analysis of mixed samples showed that the selective separation was achieved in the ABSs, including 99.47% of tartrazine in the DES-rich phase and 98.47% of sudan III in the PPG-rich phase. Additionally, the systems were successfully applied to the extraction of pigments from the actual beverage samples with recoveries ranging from 93.43% to 102.15%. Furthermore, the study on the separation mechanism indicated that the hydrogen bonding played a significant role in the separation process. All the above results highlight the proposed DES/polymer-based ABSs have great advantages in selective and high-performance separation of pigments from beverages.

One waste and two products: choosing the best operational temperature and hydraulic retention time to recover hydrogen or 1,3-propanediol from glycerol fermentation.

This study aimed to compare the production of hydrogen and 1,3-propanediol from crude glycerol (10 g/L) in mesophilic (30 °C) and thermophilic (55 °C) anaerobic fluidized bed reactors, namely AFBR30 °C and AFBR55 °C, respectively, at hydraulic retention times (HRT) reduced from 8 to 1 h. In AFBR30 °C, the absence or low hydrogen yields can be attributed to the production of 1,3-propanediol (maximum of 651 mmol/mol glycerol), and the formation of caproic acid (maximum of 1097 mg/L) at HRTs between 8 and 2 h. In AFBR55 °C, the hydrogen yield of 1.20 mol H2/mol glycerol consumed was observed at the HRT of 1 h. The maximum yield of 1,3-propanediol in AFBR55 °C was equal to 804 mmol/mol glycerol at the HRT of 6 h and was concomitant with the production of hydrogen (0.87 mol H2/mol glycerol consumed) and butyric acid (1447 mg/L).

Separation and Purification of Biogenic 1,3-Propanediol from Fermented Glycerol through Flocculation and Strong Acidic Ion-Exchange Resin.

In the present work, was investigated the separation and purification procedure of the biogenic 1,3-propanediol (1,3-PD), which is a well-known valuable compound in terms of bio-based plastic materials development. The biogenic 1,3-PD was obtained as a major metabolite through the glycerol fermentation by Klebsiella pneumoniae DSMZ 2026 and was subjected to separation and purification processes. A strong acidic ion exchange resin in H+ form was used for 1,3-PD purification from the aqueous solution previously obtained by broth flocculation. The eluent volume was investigated considering the removal of the secondary metabolites such as organic acids (acetic, citric, lactic, and succinic acids) and 2,3-butanediol (2,3-BD), and unconsumed glycerol. It was observed that a volume of 84 mL of ethanol 75% loaded with a flow rate of 7 mL/min completely remove the secondary metabolites from 10 mL of concentrated fermented broth, and pure biogenic 1,3-PD was recovered in 128 mL of the eluent.

UVA and UVB Photoprotective Capabilities of Topical Formulations Containing Mycosporine-like Amino Acids (MAAs) through Different Biological Effective Protection Factors (BEPFs).

The safety and stability of synthetic UV-filters and the procedures for evaluating the photoprotective capability of commercial sunscreens are under continuous review. The influence of pH and temperature stressors on the stability of certain Mycosporine-like amino acids (MAAs) isolated at high purity levels was examined. MAAs were highly stable at room temperature during 24 h at pH 4.5⁻8.5. At 50 °C, MAAs showed instability at pH 10.5 while at 85 °C, progressive disappearances were observed for MAAs through the studied pH range. In alkaline conditions, their degradation was much faster. Mycosporine-serinol and porphyra-334 (+shinorine) were the most stable MAAs under the conditions tested. They were included in four cosmetically stable topical sunscreens, of which the Sun Protection Factor (SPF) and other Biological Effective Protection Factors (BEPFs) were calculated. The formulation containing these MAAs showed similar SPF and UVB-BEPFs values as those of the reference sunscreen, composed of synthetic UV absorbing filters in similar percentages, while UVA-BEPFs values were slightly lower. Current in vitro data strongly suggest that MAAs, as natural and safe UV-absorbing and antioxidant compounds, have high potential for protection against the diverse harmful effects of solar UV radiation. In addition, novel complementary in vitro tests for evaluation of commercial sunscreens efficacy are proposed.

Repurposing existing drugs: identification of irreversible IMPDH inhibitors by high-throughput screening.

Inosine 5'-monophosphate dehydrogenase (IMPDH) is an essential enzyme for the production of guanine nucleotides. Disruption of IMPDH activity has been explored as a therapeutic strategy for numerous purposes, such as for anticancer, immunosuppression, antiviral, and antimicrobial therapy. In the present study, we established a luciferase-based high-throughput screening system to identify IMPDH inhibitors from our chemical library of known bioactive small molecules. The screening of 1400 compounds resulted in the discovery of three irreversible inhibitors: disulfiram, bronopol, and ebselen. Each compound has a distinct chemical moiety that differs from other reported IMPDH inhibitors. Further evaluation revealed that these compounds are potent inhibitors of IMPDHs with kon values of 0.7 × 104 to 9.3 × 104 M-1·s-1. Both disulfiram and bronopol exerted similar degree of inhibition to protozoan and mammalian IMPDHs. Ebselen showed an intriguing difference in mode of inhibition for different IMPDHs, with reversible and irreversible inhibition to each Cryptosporidium parvum IMPDH and human IMPDH type II, respectively. In the preliminary efficacy experiment against cryptosporidiosis in severe combined immunodeficiency (SCID) mouse, a decrease in the number of oocyst shed was observed upon the oral administration of disulfiram and bronopol, providing an early clinical proof-of-concept for further utilization of these compounds as IMPDH inhibitors.

Rapid and Green Separation of Mono- and Diesters of Monochloropropanediols by Ultrahigh Performance Supercritical Fluid Chromatography-Mass Spectrometry Using Neat Carbon Dioxide as a Mobile Phase.

This study demonstrates the effect of column selectivity and density of supercritical carbon dioxide (SC-CO2) on the separation of monochloropropanediol (MCPD) esters, known as food toxicants, using SC-CO2 without addition of cosolvent in ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS). This study shows that over 20 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) mono- and diesters are separated on a 2-picolylamine column in less than 12 min. The presence and position of a hydroxyl group in the structure, the number of unsaturated bonds, and the acyl chain length play a significant role in the separation of MCPD esters. The flow rate, backpressure, and column oven temperature, which affect the density of the mobile phase, were shown to have a substantial impact on retention, efficiency, and selectivity. The developed method was successfully applied for the determination of MCPD esters in refined oils and showed a close to excellent green analysis score using the Analytical Eco-Scale.

Improvement of 1,3-propanediol production using an engineered cyanobacterium, Synechococcus elongatus by optimization of the gene expression level of a synthetic metabolic pathway and production conditions.

The introduction of a synthetic metabolic pathway consisting of multiple genes derived from various organisms enables cyanobacteria to directly produce valuable chemicals from carbon dioxide. We previously constructed a synthetic metabolic pathway composed of genes from Escherichia coli, Saccharomyces cerevisiae, and Klebsiella pneumoniae. This pathway enabled 1,3-propanediol (1,3-PDO) production from cellular DHAP via glycerol in the cyanobacterium, Synechococcus elongatus PCC 7942. The production of 1,3-PDO (3.79mM, 0.29g/l) directly from carbon dioxide by engineered S. elongatus PCC 7942 was successfully accomplished. However, the constructed strain accumulated a remarkable amount of glycerol (12.6mM, 1.16g/l), an intermediate metabolite in 1,3-PDO production. Notably, enhancement of latter reactions of synthetic metabolic pathway for conversion of glycerol to 1,3-PDO increases 1,3-PDO production. In this study, we aimed to increase the observed 1,3-PDO production titer. First, the weaker S. elongatus PCC 7942 promoter, PLlacO1, was replaced with a stronger promoter (Ptrc) to regulate genes involved in the conversion of glycerol to 1,3-PDO. Second, the induction timing for gene expression and medium composition were optimized. Promoter replacement resulted in higher 1,3-PDO production than glycerol accumulation, and the amount of products (1,3-PDO and glycerol) generated via the synthetic metabolic pathway increased with optimization of medium composition. Accordingly, we achieved the highest titer of 1,3-PDO (16.1mM, 1.22g/l) and this was higher than glycerol accumulation (9.46mM, 0.87g/l). The improved titer was over 4-fold higher than that of our previous study.

Two natural compounds - a benzofuran and a phenylpropane - from Artemisia dracunculus.

The structure elucidation of three metabolites herniarin (7-methoxy-2H-chromen-2-one, 1), phytoalexin (5-acetyl-6-hydroxy-2-(1-hydroxy-1-methylethyl)benzofuran, 2), and prestragol (3-(4'-methoxyphenyl)-prop-1,2-diol, 3) isolated from Artemisia dracunculus was determined on the basis of 1D, 2D NMR methods and by an X-ray crystallographic determination.

Vortex-assisted emulsification semimicroextraction for the analytical control of restricted ingredients in cosmetic products: determination of bronopol by liquid chromatography.

Vortex-assisted emulsification semimicroextraction is proposed as a one-step solution-extraction procedure for sample preparation in cosmetic products. The procedure allows rapid preparation based on dispersion of the sample in a mixture of 1 mL of n-hexane and 0.5 mL of ethanol, followed by the addition of 0.5 mL of water and centrifugation to obtain two separated phases. This procedure provides good sample clean-up with minimum dilution and is very useful for the determination of ingredients with restricted concentrations, such as bronopol. The procedure was applied to the determination of bronopol by liquid chromatography with UV detection. The best chromatographic separation was obtained by using a C18 column set at 40 °C and performing a stepwise elution with a mixture of ethanol/aqueous 1 % acetic acid solution as mobile phase pumped at 0.5 mL min(-1). The detection wavelength was set at 250 nm and the total run time required was 12 min. The method was successfully applied to 18 commercial cosmetic samples including creams, shampoos, and bath gels. Good recoveries and repeatability were obtained, with a limit of detection of 0.9 µg mL(-1), which makes the method suitable for the analytical control of cosmetic products. Moreover, it could be considered environmentally friendly, because water, ethanol, and only a low volume of n-hexane are used as solvents.

Cyanobacterial production of 1,3-propanediol directly from carbon dioxide using a synthetic metabolic pathway.

Production of chemicals directly from carbon dioxide using light energy is an attractive option for a sustainable future. The 1,3-propanediol (1,3-PDO) production directly from carbon dioxide was achieved by engineered Synechococcus elongatus PCC 7942 with a synthetic metabolic pathway. Glycerol dehydratase catalyzing the conversion of glycerol to 3-hydroxypropionaldehyde in a coenzyme B12-dependent manner worked in S. elongatus PCC 7942 without addition of vitamin B12, suggesting that the intrinsic pseudovitamin B12 served as a substitute of coenzyme B12. The highest titers of 1,3-PDO (3.79±0.23 mM; 288±17.7 mg/L) and glycerol (12.62±1.55 mM; 1.16±0.14 g/L), precursor of 1,3-PDO, were reached after 14 days of culture under optimized conditions in this study.

Debottlenecking product inhibition in 1,3-propanediol fermentation by In-Situ Product Recovery.

The present work describes the application of liquid-liquid extraction as an In-Situ product recovery (ISPR) technique to overcome the problem of product inhibition in 1,3-PD fermentation. As a part of initial screening experiments, six solvents were subjected to phase separation and biocompatibility tests to find the best extractant for in-situ removal of 1,3-PD from the bioreactor. These included tributylphosphate, ethyl acetate, butyl acetate, oleyl alcohol, oleic acid and hexanol. Of these, ethyl acetate was found to be the most suitable solvent for 1,3-PD extraction. Use of the selected extractant in continuous integrated fermentation-extraction was established by batch and fed-batch extractive fermentations which demonstrated a significantly improved 1,3-PD production of 35g/L and 74.5g/L, respectively. A steady state 1,3-PD concentration of 58g/L was obtained in continuous extractive system. Continuous cultivation with in-situ cell retention and in-situ 1,3-PD removal demonstrated a 5-fold enhancement in 1,3-PD productivity over non-extractive batch.

Microbial community structure and dynamics in a membrane bioreactor supplemented with the flame retardant dibromoneopentyl glycol.

Brominated flame retardants (BFRs) are a group of widely used compounds that, due to their limited biodegradability, exhibit excessive persistence in the environment. The persistence and high toxicity of these compounds to the natural biota causes great environmental concern. We investigated the biodegradation of the BFR dibromoneopentyl glycol (DBNPG) under continuous culture conditions using a miniature membrane bioreactor (mMBR) to assess its feasibility as a bioremediation approach. This system demonstrated long-term, stable biodegradation of DBNPG (>90 days), with an average removal rate of about 50%. Pyrosequencing of the 16S rRNA gene of the microorganisms involved in this process revealed the dominance of reads affiliated with the genus Brevundimonas of the Alphaproteobacteria class during the different mMBR operational stages. The bacterial community was also dominated by reads affiliated with the Sinorhizobium and Sphingopyxis genera within the Alphaproteobacteria class and the Sediminibacterium genus of the Sphingobacteria class. Real-time PCR used to analyze possible changes in the population dynamics of these four dominant groups revealed their consistent presence throughout the long-term mMBR biodegradation activity. Two genera, Brevundimonas and Sphingopyxis, were found to increase in abundance during the acclimation period and then remained relatively stable, forming the main parts of the consortium over the prolonged active stage.

Multiplicity of steady states in a bioreactor during the production of 1,3-propanediol by Clostridium butyricum.

In recent decades, the production of compounds from microorganisms has increased significantly. Glycerol as a source of substrate appears to have great potential, due to its large supply because of the increase in biodiesel production. This paper will discuss the multiplicity of steady states for the production of 1,3-propanediol from glycerol by Clostridium butyricum, employing a model that takes into account inhibition by fermentation products. The theoretical study of bifurcation enabled us to make a qualitative adjustment to the various experimental steady states, using the theoretical steady states obtained from the AUTO2007 program. The theoretical model parameters were varied to fit qualitatively the values of the experimental steady states. In addition, this work is a qualitative study, using experimental steady states that can be used as an initial study for more advanced work on optimizing the production of 1,3-propanediol.

Integrated study of fermentation and downstream processing in a miniplant significantly improved the microbial 1,3-propanediol production from raw glycerol.

In this work, an integrated and optimized production process for 99 % pure 1,3-propanediol (PDO) from raw glycerol is presented. Glycerol fermentation is carried out applying a newly isolated strain Clostridium pasteurianum K1 under non-sterile conditions without any complex ingredients in the fermentation media. In this environment over 55 g/L PDO, yields of 0.52 g/g and space time yields over 2.3 g/(Lh) were achieved in up to 1 m(3) pilot scale. The downstream process for PDO purification consists of an ultrafiltration for biomass and protein separation, an evaporation step for concentration of PDO and a two-step rectification for final purification. For a proof of concept, process optimization and especially investigation of interactions of individual steps, the downstream process was performed in miniplant scale. A minimum salt input into the downstream process was shown to be important to overcome precipitation in evaporation as well as rectification. Thus, raw glycerol is desalinated before fermentation and the fermentation medium was minimized and complex nutrients, such as yeast extract, were avoided totally to prevent furthermore dark color formation. Furthermore, by titration of fermentation with ammonia instead of sodium hydroxide, the later separation of the major by-products, organic acids, in the evaporation step was significantly enhanced.

Identification of 3-chloro-1,2-propandiol using molecularly imprinted composite solid-phase extraction materials.

A novel molecularly imprinted material based on silica microparticles was synthesized by surface polymerization with 3-chloro-1,2-propandiol (3-MCPD) as a template molecule. The molecularly imprinted polymer (MIP) was characterized by infrared spectroscopy and scanning electron microscopy. The adsorption of 3-MCPD by MIP was measured by gas chromatography with electron capture detection (GC-ECD) and an equilibrium binding experiment. Scatchard analysis revealed that the maximum apparent binding capacities of the MIP and non-imprinted polymer (NIP) were 67.64 and 23.31 µmol/g, respectively. The new adsorbent was successfully used in solid-phase extraction (SPE) to selectively enrich and determine 3-MCPD in soy sauce samples. The MIP-SPE column achieves recoveries higher than 92.7% with a relative standard deviation of less than 1.83%. The MIP-SPE-GC protocol improved the selectivity and eliminated the effects of template leakage on quantitative analysis and could be used for the determination of 3-MCPD in other complex food samples.

A new phenylpropanoid and an alkylglycoside from Piper retrofractum leaves with their antioxidant and α-glucosidase inhibitory activity.

Two new compounds, piperoside (1) and isoheptanol 2(S)-O-ß-D-xylopyranosyl (1→6)-O-ß-D-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-ß-D-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-ß-D-glucopyranoside (5), icariside F2 (6), dihydrovomifoliol-3'-O-ß-D-glucopyranoside (7), isopropyl O-ß-D-glucopyranoside (8), isopropyl primeveroside (9), n-butyl O-ß-D-glucopyranoside (10), isoheptanol 2(S)-O-ß-D-apiofuranosyl-(1→6)-O-ß-D-glucopyranoside (12), were isolated from the leaves of Piper retrofractum. Their structures were determined from 1D-NMR, 2D-NMR, and HR-ESI-MS spectral, a modified Mosher's method, and comparisons with previous reports. All of the isolated compounds showed modest α-glucosidase inhibitory (4.60±1.74% to 11.97±3.30%) and antioxidant activities under the tested conditions.

Enhancing trimethylolpropane esters synthesis through lipase immobilized on surface hydrophobic modified support and appropriate substrate feeding methods.

Candida sp. 99-125 lipase immobilized on surface hydrophobic modified support and appropriate substrate feeding methods were used to improve the synthesis of tri-substituted trimethylolpropane (TMP) esters, which can be used as raw materials for biodegradable lubricants. The proposed novel production method is environmentally friendly. Lipase was adsorbed on surface hydrophobic silk fibers that were pretreated by amino-modified polydimethylsiloxane. A 5-level-4-factors central composite model, including reaction time, temperature, enzyme amount, and molar ratio of fatty acid to TMP, was designed to evaluate the interaction of process variables in the enzymatic esterification. The water activity was kept constant using a LiCl-saturated salt solution. Under the optimum conditions with 30% enzyme amount and substrates molar ratio 8.4 at 45°C for 47h, the total conversion of caprylic acid is 97.3% and the yield of tri-substituted TMP esters is 95.5%. The surface hydrophobic treatment resulted in less cluster water accumulated on the surface immobilized lipase, which was demonstrated by near-infrared spectra. Consequently, the optimum temperature and water tolerance of immobilized lipase were increased. Two TMP-feeding methods were used to maintain high molar ratio of fatty acid to TMP, and increase the final tri-substituted TMP esters content exceeding 85% (w/w) in reactant.

Five new compounds from Rhododendron mariae Hance.

Five new compounds (-)-(7R,8S,7'R,8'S)-4,9,4',9'-tetrahydroxy-3,3'-dimethoxy-7,7'-epoxylignan 9-O-ß-d-xylopyranoside (1), (-)-(7'R,8'S)-5'-methoxyl(dimeric coniferyl acetate) (2), (+)-(1R,2S)-1,2-bis(4-hydroxy-3-methoxyphenyl)-3-acetyl-1,3-propanediol (3), (-)-3-((2R,3R)-2-ethoxy-3-(hydroxymethyl)-7-methoxy-2,3-dihydrobenzofuran-5-yl)propan-1-ol (4), and (+)-3-((2S,3S)-2-ethoxy-3-(hydroxymethyl)-7-methoxy-2,3-dihydrobenzofuran-5-yl)propan-1-ol (5), together with 12 known compounds, were isolated from an ethanol extract of the dried stems of Rhododendron mariae Hance. Their structures were elucidated by NMR, HR-MS, CD, ORD experiments and chemical methods. Compounds 2, 3, 6, and 17 exhibited significant inhibitory effects on the nitric oxide production in lipopolysaccharide activated C57BL6/J mouse macrophages.

Sorption equilibrium, mechanism and thermodynamics studies of 1,3-propanediol on beta zeolite from an aqueous solution.

To identify the adsorption characteristics of 1,3-propanediol on beta zeolite, the effects of temperature, zeolite dose, and 1,3-propanediol concentration were studied through batch experiments. The results showed that the pseudo-second order model expressed the kinetic data better. The experimental and theoretical adsorption capacities were 116.2 and 119.0 mg/g at 293 K, respectively. The adsorption equilibrium data were observed to satisfy the Freundlich isotherm model. Based on the Boyd plot, intraparticle diffusion primarily governed the uptake process. Moreover, thermodynamic parameters, such as changes in standard free energy (ΔG(0)), standard enthalpy (ΔH(0)), and standard entropy, were estimated. The negative values of ΔG(0) and ΔH(0) (-9.4 kJ/mol) indicated that the adsorption process was spontaneous, exothermic, and feasible. Finally, the activation energy derived from the Arrhenius equation suggested that the interaction mainly constitute physical adsorption.

Experimental and theoretical investigation of multistage extraction of 1,3-propanediol using the extraction system phosphate/1-butyl-3-methylimidazolium trifluoromethanesulfonate/water.

The separation of 1,3-propanediol from fermentation broth is a challenging and energy-demanding step using conventional unit operations. One alternative process is the use of an aqueous two-phase system incorporating ionic liquids to use synergy effects of both technologies. Within this manuscript, the technical feasibility of the extraction of 1,3-propanediol using the aqueous two-phase system phosphate (salt)/1-butyl-3-methylimidazolium trifluoromethanesulfonate (ionic liquid)/water in a continuously operated process in pilot-scale is presented. The extraction was performed in a multistage mixer-settler unit and successfully modeled with an equilibrium-stage model and correlations to describe the liquid-liquid equilibrium of the salt/ionic liquid/water two-phase system. The developed and validated model was used for a further investigation of the influence of different process parameters in the determined operating window. Theses parameters include the number of stages, the phase ratio, the pH, and the mass fraction of the involved components. The results prove that the phosphate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate mass fraction, the phase ratio, and the number of stages have a considerable influence on the recovery of 1,3-propanediol, whereas the pH value has only a smaller impact. Those results can be used for optimization of the system as well as for targeting future research within this area.