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Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of an organic alkali was applied to the direct analysis of copolymer composition for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] accumulated in whole bacterial cells. Cupriavidus necator was grown on a liquid medium with different molar ratios of valeric acid (V) to glucose (G) in order to control the compositions of P(3HB-co-3HV) produced in the cells. Trace amounts (0.03 mg) of dried Cupriavidus necator cells were directly subjected to THM-GC in the presence of tetramethylammonium hydroxide (TMAH) at 400 C. The obtained chromatograms clearly showed nine characteristic peaks, attributed to the THM products from 3HB and 3HV units in the polymer chains, without any appreciable interference by the bacterial matrix components. Based on these peak intensities, the copolymer compositions were determined rapidly without using any cumbersome sample pretreatment. Moreover, the compositions thus obtained were in good agreement with those obtained by the conventional technique.Keywords Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), thermally assisted hydrolysis and methylation-GC, tetramethylammonium hydroxide, copolymer composition

Abstract:There is considerable interest in the development of simple methods for quantifying production of the biodegradable polyester poly(3-hydroxybutyrate) [P(3HB)] by bacteria. Cells of Cupriavidus necator were grown on agar medium containing different concentrations of glucose (10-25 g/L) as a sole carbon source. Trace amounts (100 ± 5 μg) of dried C. necator cells were directly subjected to thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of tetramethylammonium hydroxide (TMAH). On the resulting chromatograms, a series of characteristic peaks, attributed to the THM products from poly(3-hydroxybutylate) accumulated in the bacterial cells, were clearly observed without any interfering component. Based on the peak intensities, the contents of P(3HB) in C. necator were determined precisely and rapidly without using any cumbersome sample pretreatment. Furthermore, the values of the P(3HB) contents coincided overall with those obtained by the conventional method involving solvent extraction followed by gravimetric determination.

Ti-Ni shape memory alloy is used for bio-medical and industrial fields even if Ni is a substance which has strong allergic nature and carcinogenicity to a human body, then, Ti-Ni alloy system is in a prohibition tendency in the medical field in Europe in recent years. Therefore, Ni-free shape memory alloy is desired in the near future medical field. In this research, we pay our attention to the Ti-Nb alloy which has shape memory as well as superelastic effects. The Ti-Nb fiber was fabricated by using the ark melting and nozzelless rapid solidification method. The fiber samples were used to investigate the following characteristics relating with shape memory effect, that is to say, (1) cross sectional microstructure observation, (2) DSC(phase transformation temperature changes) , (3) temperature-shape recovery relationship. Moreover, heat-treated effect on shape recovery phenomena was observed in comparison with the starting bulk material. Finally, the fundamental discussion to correlate the rapid-solidification process condition with the characteristic of Ti-Nb shape memory alloy for bio-medical engineering application was conducted.