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A combination of metal-supported catalysts with vesicles successfully achieved a conversion of glycerol to lactic acid (lactate) under mild heated and alkaline condition. A high reaction yield (reaction temperature: 333 K; yield: 90% for 24 h) was achieved, which was an environmentally-friendly reaction process.A combination of metal-supported catalysts with vesicles successfully achieved a conversion of glycerol to lactic acid (lactate) under the mild heated and alkaline condition. The high reaction yield (reaction temperature: 333 K; yield: 90% for 24 h) was achieved, which was an environmentally-friendly reaction process. The vesicles posssibly contributed to the hydrogene subtraction from glycerol.

After a nascent chain of a membrane protein emerges from the ribosomal tunnel, the protein is integrated into the cell membrane. This process is controlled by a series of proteinaceous molecular devices, such as signal recognition particles and Sec translocons. In addition to these proteins, we discovered two endogenous components regulating membrane protein integration in the inner membrane of Escherichia coli. The integration is blocked by diacylglycerol (DAG), whereas the blocking is relieved by a glycolipid named membrane protein integrase (MPIase). Here, we investigated the influence of these integration-blocking and integration-promoting factors on the physicochemical properties of membrane lipids via solid-state NMR and fluorescence measurements. These factors did not have destructive effects on membrane morphology because the membrane maintained its lamellar structure and did not fuse in the presence of DAG and/or MPIase at their effective concentrations. We next focused on membrane flexibility. DAG did not affect the mobility of the membrane surface, whereas the sugar chain in MPIase was highly mobile and enhanced the flexibility of membrane lipid headgroups. Comparison with a synthetic MPIase analog revealed the effects of the long sugar chain on membrane properties. The acyl chain order inside the membrane was increased by DAG, whereas the increase was cancelled by the addition of MPIase. MPIase also loosened the membrane lipid packing. Focusing on the transbilayer movement, MPIase reduced the rapid flip-flop motion of DAG. On the other hand, MPIase could not compensate for the diminished lateral diffusion by DAG. These results suggest that by manipulating the membrane lipids dynamics, DAG inhibits the protein from contacting the inner membrane, whereas the flexible long sugar chain of MPIase increases the opportunity for interaction between the membrane and the protein, leading to membrane integration of the newly formed protein.

The release behavior of substrates encapsulated in the vesicle can be controlled by the interaction between the vesicular membrane and the protein. However, its control mechanism is still now unknown. Therefore, the protein–vesicle interaction was investigated by a π–Aisotherm. It was clarified that the released amount of encapsulated substrates increased with increasing protein–vesicle interaction. This result leads to the development of drug delivery systems (DDS) and of biosensor technology.It was found that the leakage rate of calcein tended to increase as the protein penetrated into vesicle membranes, regardless of the composition of lipids or the type of proteins with different molecular weight or charge. The present finding is helpful for a development of biosensor and drug delivery systems.

Aggregates of amphiphilic molecules can be used as drug carriers, for which the properties can be modified by mixing with other molecules such as cholesterol. It is important to understand the effects of such additives on the properties because they directly define the material functions. In this work, we investigated the effect of cholesterol on the formation and hydrophobicity of aggregates of sorbitan surfactants. As cholesterol changed its formation from micelles to vesicles, an increase in hydrophobicity was seen, particularly in the middle regions compared with the shallow and deep regions. We show that this gradual hydrophobicity is related to the localization of the embedded molecules. 4-Hydroxy-TEMPO and 4-carboxy-TEMPO were preferentially localized in the shallow region of the aggregates, whereas 4-PhCO2-TEMPO was preferentially localized in the deep region of the vesicle. The localization of molecules depends on their chemical structure. However, the localization of 4-PhCO2-TEMPO in micelles was not observed, despite the similar hydrophobicity in the hydrophobic region within the aggregates. The localization of embedded molecules was related to other properties, such as molecular mobility.

AbstractHydrothermal carbonization of peels of Carya cathayensis sarg(PCCS) by subcritical water or acetone- and ethanol-modified subcritical water was carried out at the temperature from 280 to 360°C and coal-like hydrochar was obtained. The hydrochar yield decreased with increasing of treatment temperature, but the higher heating value (HHV) and carbon content of hydrochar were promoted at higher treatment temperature. The HHV of hydrochar was in range of 30–46 MJ/kg with an increase from 52.4 to 127.6%, compared to the original PCCS. The HHVs of hydrochars obtained at 360°C could be comparable with those of heavy fuel oil (42.9 MJ/kg) and diesel oil (45.7 MJ/kg). The O/C and H/C values of hydrochar were similar to those of lignite and subbituminous, except the ash content. Especially, the O/C and H/C values of hydrochars prepared at 360°C could be compatible with those of bituminous. When treated with acetone- or ethanol-modified subcritical water, a synergistic effect of acetone–water or ethanol–water for hydrothermal carbonization was observed; the liquefaction rate with acetone–water or ethanol–water mixture was larger than that of water or acetone or ethanol only. There was no significant change on the O/C and H/C values and HHV on the hydrochar, although more PCCS, was decomposed when using acetone–water or ethanol–water mixture.

Hydrothermal carbonization of peels of Carya cathayensis sarg(PCCS) by subcritical water or acetone- and ethanol-modified subcritical water was carried out at the temperature from 280 to 360°C and coal-like hydrochar was obtained. The hydrochar yield decreased with increasing of treatment temperature, but the higher heating value (HHV) and carbon content of hydrochar were promoted at higher treatment temperature. The HHV of hydrochar was in range of 30–46 MJ/kg with an increase from 52.4 to 127.6%, compared to the original PCCS. The HHVs of hydrochars obtained at 360°C could be comparable with those of heavy fuel oil (42.9 MJ/kg) and diesel oil (45.7 MJ/kg). The O/C and H/C values of hydrochar were similar to those of lignite and subbituminous, except the ash content. Especially, the O/C and H/C values of hydrochars prepared at 360°C could be compatible with those of bituminous. When treated with acetone- or ethanol-modified subcritical water, a synergistic effect of acetone–water or ethanol–water for hydrothermal carbonization was observed; the liquefaction rate with acetone–water or ethanol–water mixture was larger than that of water or acetone or ethanol only. There was no significant change on the O/C and H/C values and HHV on the hydrochar, although more PCCS, was decomposed when using acetone–water or ethanol–water mixture.

The liposome immobilized on indium tin-oxide electrode was prepared as a “Membrane Chip” to evaluate the liposome-liposome interaction. Three kinds of neutral liposomes entrapping the fluorescence probe, calcein, were utilized as a sensory liposome. Twenty four kinds of liposomes were used to construct a membrane library based on the calcein release behavior. The loading of liposome including the unsaturated phospholipid into the dialyzer induced the variation of surface state of liposome membrane. We analyzed the above liposome by a comparison of it with the membrane library constructed by Membrane Chip. The liposome after its dialysis treatment was found to show the membrane property of the liposome with domain-like structure prior to the interaction with amyloid β protein. Also the above liposome showed the oxidized liposome-like membrane property. In conclusion, we demonstrated a membrane library-based method to evaluate the surface state of the model biomembranes with unclear surface property.

Liposome-loaded membrane module (LLM) was prepared in hollow fiber module (HF-LLM), where the liposome was loaded into the hollow fiber membrane. The filtration property of the LLM was characterized. The oxidized and fragmented superoxide dismutase (SOD) was applied to the prepared LLM to separate the peptide to give a SOD-like activity on the liposome membrane, resulting in the recovery of the specific peptide. It was found that the SOD-like activity could be obtained in the SOD LIPOzyme prepared, resulting in the effective elimination of the superoxide in the HF-LLM.

Liposome-loaded membrane module (LLM) was prepared in hollow fiber module (HF-LLM), where the liposome was loaded into the hollow fiber membrane. The filtration property of the LLM was characterized. The oxidized and fragmented superoxide dismutase (SOD) was applied to the prepared LLM to separate the peptide to give a SOD-like activity on the liposome membrane, resulting in the recovery of the specific peptide. It was found that the SOD-like activity could be obtained in the SOD LIPOzyme prepared, resulting in the effective elimination of the superoxide in the HF-LLM.

The liposome immobilized on indium tin-oxide electrode was prepared as a “Membrane Chip” to evaluate the liposome-liposome interaction. Three kinds of neutral liposomes entrapping the fluorescence probe, calcein, were utilized as a sensory liposome. Twenty four kinds of liposomes were used to construct a membrane library based on the calcein release behavior. The loading of liposome including the unsaturated phospholipid into the dialyzer induced the variation of surface state of liposome membrane. We analyzed the above liposome by a comparison of it with the membrane library constructed by Membrane Chip. The liposome after its dialysis treatment was found to show the membrane property of the liposome with domain-like structure prior to the interaction with amyloid β protein. Also the above liposome showed the oxidized liposome-like membrane property. In conclusion, we demonstrated a membrane library-based method to evaluate the surface state of the model biomembranes with unclear surface property.

Bicelle is one of the most stable phospholipid assemblies, which has tremendous applications in the research areas for drug delivery or structural studies of membrane proteins owing to its bio-membrane mimicking characteristics and high thermal stability. However, the conventional preparation method for bicelle demands complicated manufacturing processes and a long time so that the continuous synthesis method of bicelle using microfluidic chip has been playing an important role to expand its feasibility. We verified the general availability of hydrodynamic focusing method with microfluidic chip for bicelle synthesis using various kinds of lipids which have a phase transition temperature ranged from − 2 to 41 °C. Bicelle can be formed only when the inside temperature of microfluidic chip was over the phase transition temperature. Moreover, the concentration condition for bicelle formation varied depending on the lipids. Furthermore, the transition process characteristics from bicelle to vesicle were analyzed by effective q-value, mixing time and dilution condition. We verified that the size of transition vesicles was controlled according to the effective q-value, mixing time, and temperature.

Abstract: The aggregation behavior of N-dodecanoyl-l-tryptophan within a liposome membrane was investigated by fluorescence spectroscopy. Liposomes with a mean diameter of 100 nm, formed from either 1-2-dilauroyl-sn-glycero-3-phosphocholine, 1-2-myristoyl-sn-glycero-3-phosphocholine, or 1-2-palmitoyl-sn-glycero-3-phosphocholine, were used. Fluorescence measurements indicate that the sodium salt of N-dodecanoyl-l-tryptophan forms domains with the liposome membranes below the main phase transition temperature, T m. Above T m, the molecules are homogeneously dispersed in the liquid crystalline state of the membranes.

The possibility of the translocation of the enzyme across the phospholipid bilayer membrane was investigated by using the liposomes prepared by 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) in which β‐galactosidase (β‐gal) was entrapped. Exposing the POPC liposomes entrapping β‐gal inside to heat treatment (40–50 °C, 1–60 min) was found to induce its translocation across the liposome membrane. The translocated activity of β‐gal from inner to outer aqueous phase of liposomes indicated the maximal value when the liposomes entrapping β‐gal were heated at 45 °C for 30 min. The gel permeation profiles of the liposomes before and after heat treatment (45 °C, 30 min) also supported the translocation of β‐gal across the liposome membrane. The membrane fluidity of liposomes was found to be increased with increasing temperature, so that the hydrophobicity of liposome membrane was also increased. The local hydrophobicity of β‐gal was maximized at the temperature of 40–50 °C. The mechanisms of β‐gal translocation have been suggested to be triggered by the enhancement of hydrophobic interaction between the liposome surface and β‐gal molecules. Finally, a minimal scheme of possible mechanism on the heat‐induced translocation of β‐gal has been presented on the basis of the hydrophobic interaction between the liposome and the proteins. The experimental data on the heat‐induced translocation of β‐gal were well corresponding to those from model calculation.

A rapid conversion of glycerol to lactic acid (lactate) could be successfully achieved under alkaline hydrothermal conditions, by using a continuous flow reaction system. A rapid conversion by a continuous flow-type reaction system made it possible to achieve the reaction under high-temperature conditions without side reactions. The rapid conversion and high reaction yield (reaction: 2 min; yield: 90%) resulted from the rapid temperature-shift advantageous for the inhibition of side reactions.

Aggregates in aqueous solutions can embed hydrophobic molecules, and their interactions depend on the properties of the aggregates. The electric surface potential, molecular mobility, and gradual hydrophobicity are the properties that regulate the interactions, and it is essential to understand these to quantify the properties. Electric surface potential and molecular mobility are quantified using the zeta potential and NMR measurements. In this study, the quantification of gradual hydrophobicity within the aggregate based on the relative permittivity, also called the dielectric constant, has been estimated from fluorescence spectra of pyrene–dicarboxylic acid conjugates. The localization of the pyrene moiety was modified by conjugation with succinic acid, suberic acid, or dodecanedioic acid, and the conjugates were evaluated in the shallow, middle, and deep regions of the aggregates. Span and Tween surfactants have been employed to prepare these aggregates, because they form various kinds of aggregates such as micelles and vesicles. It was realized that the hydrophobicity gradually increased from the interface to the hydrophobic core. Alternatively, a comparison of hydrophobicity within the aggregates showed no remarkable difference. Moreover, the analyses suggested that there are a few water molecules in the deep region. These results support the idea of the localization of embedded molecules in aggregates.

The objective of this review is to survey the development of the optimization of lyophilization. The optimization study of the lyophilizer has been roughly developing by the order of (i) trial-and-error approach, (ii) process modeling using mathematical models, (iii) scalability, and (iv) quality-by-design. From the conventional lyophilization studies based on the trial-and-error, the key parameters to optimize the operation of lyophilization were found out, i.e., critical material attributes (CMAs), critical process parameters (CPPs), and critical quality attributes (CQAs). The mathematical models using the key parameters mentioned above have been constructed from the viewpoints of the heat and mass transfer natures. In many cases, it is revealed that the control of the primary drying stage determines the outcome of the lyophilization of products, as compared with the freezing stage and the secondary drying stage. Thus, the understanding of the lyophilization process has proceeded. For the further improvement of the time and economical cost, the design space is a promising method to give the possible operation range for optimizing the lyophilization operation. This method is to search the optimized condition by reducing the number of key parameters of CMAs, CPPs, and CQAs. Alternatively, the transfer of lyophilization recipe among the lab-, pilot-, and production-scale lyophilizers (scale-up) has been examined. Notably, the scale-up of lyophilization requires the preservation of lyophilization dynamics between the two scales, i.e., the operation of lab- or pilot-scale lyophilizer under HEPA-filtrated airflow condition. The design space determined by focusing on the primary drying stage is large and involves the undesired variations in the quality of final products due to the heterogeneous size distribution of ice crystals. Accordingly, the control of the formation of the ice crystal with large size gave impact on the product quality and the productivity although the large water content in the final product should be improved. Therefore, the lyophilization should take into account the quality by design (QbD). The monitoring method of the quality of the product in lyophilization process is termed the “process analytical technology (PAT).” Recent PAT tools can reveal the lyophilization dynamics to some extent. A combination of PAT tools with a model/scale-up theory is expected to result in the QbD, i.e., a quality/risk management and an in situ optimization of lyophilization operation.

The hydrolysis of disaccharides was conducted using a microcapillary system under hydrothermal conditions (up to 190°C at 10 MPa and pH 4–11). The hydrolysis reaction showed a sigmoidal progression with time, especially under alkaline conditions. Analysis using a kinetic model yielded the reaction induction period. The specific pH value (pHamb) at the induction time, which is the pH value corresponding to the progression of disaccharide hydrolysis, was peculiar to each disaccharide. Finally, the calculation of the electron density around the oxygen atom of the glycosidic bond between saccharides was found to roughly predict the pHamb value required for the progression of hydrolysis.