Growth Suppression of a Robust Bacterium Methylobacterium extorquens by Porous Materials with Oxygen Functional Groups.

Suppressing the growth of Methylobacterium species without the use of toxic chemicals has been a challenging task owing to their robustness against previous antimicrobial techniques. In this work, we prepared porous materials with various numbers and types of oxygen functional groups and investigated their ability to suppress the growth of Methylobacterium extorquens. It turned out that the number and type of oxygen functional groups in the porous materials greatly affected the growth of the bacterium. Three porous materials (resorcinol-formaldehyde gel (RF), hydrothermally treated RF (RFH), and Wakkanai siliceous shale (WS)) were tested, and RF exhibited the best performance in suppressing the growth of the bacterium. This performance is possibly due to abundant phenolic groups in the porous material.

Mass preparation of oligosaccharides by the hydrolysis of chondroitin sulfate polysaccharides with a subcritical water microreaction system.

The biological functions of chondroitin sulfate (CS) are executed by the interaction of specific oligosaccharide sequences in the polysaccharide chain with effective proteins. Thus, CS oligosaccharides are expected to have pharmacological applications. Furthermore, the demand for CS in health food supplements and medication is growing. However, the absorbency of CS polysaccharides in the digestive system is very low. Since the activity of orally administered CS is expected to increase by depolymerization, industrial production of CS oligosaccharides is required. In this study, hydrolysis with subcritical and super-critical water was applied to the depolymerization of CS for the first time, and hydrolytic conditions for oligosaccharide production were examined. CS oligosaccharides principally containing an N-acetyl-D-galactosamine residue at their reducing ends were successfully obtained. No significant desulfation was found in CS oligosaccharides prepared under optimized conditions. The production of CS oligosaccharides by this method will have a strong influence on the CS-related materials market.

Highly efficient chemoselective N-acylation with water microreaction system in the absence of catalyst.

A high-speed, highly efficient chemoselective N-acylation by anhydride was achieved in the absence of catalyst for exothermic (DeltaH>0) and endothermic (DeltaH<0) acylation of various amines and anilines with the microreaction system of ambient water (micro-onH2O) and subcritical water (micro-subH2O), where the desired N-acylated products are chemoselectively obtained with high yield(s) and excellent selectivity (>95%).

Characterization and structural investigation of fractal porous-silica over an extremely wide scale range of pore size.

We have succeeded in creating Menger sponge-like fractal body, i.e., porous-silica samples with Menger sponge-like fractal geometries, by a novel template method utilizing template particles of alkylketene dimer (AKD) and a sol-gel synthesis of tetramethyl orthosilicate (TMOS). We report here the first experimental results on characterization and structural investigations of the fractal porous-silica samples prepared with various conditions such as calcination temperature and packing condition of the template particles. In order to characterize the fractal porous-silica samples, pore volume distribution, porosity and specific surface area were measured over an extremely wide scale from 1 nm to 100 microm by means of mercury porosimetry, (1)H NMR cryoporometry, nitrogen gas adsorption experiments together with direct evaluations of cross-sectional fractal dimension D(cs), and size limits of D(cs). We have found that the pore volume distribution and specific surface area of the fractal porous-silica samples can be discussed in terms of different fractal porous structures at different scale regions.