Nobuki Hayase

Isolation and characterization of poly(butylene succinate-co-butylene adipate)-degrading microorganism

Poly(butylene succinate-co-butylene adipate) (PBSA)-degrading bacterium, strain 1-A, was isolated from soil. Strain 1-A was identified as Bacillus pumilus on the basis of its physiological properties and partial 16S rRNA gene sequence. Strain 1-A also degraded poly(butylene succinate) (PBS) and poly(epsilon-caprolactone). On the other hand, poly(butylene adipate terephthalate) and poly(lactic acid) were minimally degraded by strain 1-A. The NMR spectra of degradation products from PBSA indicated that the adipate units were more rapidly degraded than 1,4-butanediol and succinate units. This seems to be one of the reasons why strain 1-A degraded PBSA faster than PBS.

Isolation and characterization of Aeromonas sp. B-5 capable of decolorizing various dyes

Aeromonas sp. B-5, which has the ability to decolorize azo dyes, was isolated from soil. Aeromonas sp. B-5 completely decolorized 100 mg/l of Bordeaux S by reductive cleavage of azo bonds under static conditions in 24 h. Though the decolorization of Bordeaux S by Aeromonas sp. B-5 was suppressed under shaking, rapid decolorization was observed when the culture was changed to static conditions after cultivation with shaking. The indigoid dye, Acid blue 74, was decolorized by Aeromonas sp. B-5 under shaking conditions, in contrast to the decolorization of azo dyes.

Polymer film produced by a marine bacterium.

Biojelly is a sort of polymer that is formed on a cellulose acetate membrane immersed in seawater. Interestingly, Biojelly inhibits attachment of marine organisms such as algae and barnacles. We could successfully isolate several marine microorganisms from Biojelly-attached microorganisms. One of these isolates, strain SHY1-1, produced water-insoluble polymeric materials in natural seawater supplemented with yeast extracts and glucose. This strain was assigned to be Alteromonas sp. by the method of the 165 rRNA gene sequencing and phylogenetic analysis. Biojelly and the polymer film produced by Alteromonas sp. SHY1-1 were qualitatively characterized by Fourier transformed infrared (FT-IR) spectroscopy and thin-layer chromatography (TLC). The result indicated that naturally occurring Biojelly and the polymeric materials obtained in this work both were a sort of mucopolysaccharide consisting of amino sugars. In addition, the attachment assay with larvae indicated that both polymer films had similar anti-fouling activity against barnacle (Balanus amphitrite).

Isolation and characterization of Bradyrhizobium sp. 224 capable of degrading sulfanilic acid.

A bacterial strain (strain 224), which has the ability to utilize sulfanilic acid as a sole source of carbon, was isolated from soil. 16S rRNA gene sequence obtained from strain 224 exhibited 100% identical to that of species in the genus Bradyrhizobium. Strain 224 degraded 4.7 mM of sulfanilic acid and released almost the same molar concentration of sulfate ion

Anodic reactions of NADH model compound by utilizing both light irradiation and riboflavin as a redox mediator

ABSTRACT Both light and a redox mediator riboflavin (RF) were utilized to promote the electro-oxidation of an NADH model compound (1-benzyl-1,4-dihydronicotinamide, BNAH), which is a key process for enzymatic biofuel cells to obtain a high performance. At the cathode, H+ ions were simultaneously reduced to produce H2 gas. To elucidate the cell reactions of this photogalvanic cell, which is significant information about the fabrication of enzymatic biofuel cells with a high performance, the effect of the BNAH and RF concentrations on the cell current, the light wavelength dependence on the current, and reduction of the RF concentration were evaluated. The obtained results strongly suggest that the anodic reactions were composed of the following reactions: 1) the photo-excitation of RF, 2) the attack of the excited RF on the BNAH and the generation of the radical species of BNAH and RF, and 3) the chain reactions between the radical species. Graphical Abstract The RF-mediated oxidation of BNAH was composed of 1) the photo-excitation of RF, 2) the attack of the excited RF on the BNAH, and 3) the chain reactions between their radicals.