Enhanced degradation of 4-aminobenzenesulfonate by a co-culture of Afipia sp. 624S and Diaphorobacter sp. 624L.

Two strains, Afipia sp. 624S and Diaphorobacter sp. 624L, were isolated from an enrichment culture with 4-aminobenzenesulfonate (4-ABS) as the only carbon source. Strain 624S utilized 4-ABS as the only source of carbon and energy and degraded 3.8 mM 4-ABS in 2 weeks, releasing a small amount of sulfate ions. On the other hand, strain 624L did not utilize 4-ABS. Additionally, a co-culture of strains 624S and 624L resulted in the enhanced degradation of 4-ABS, and no sulfite was accumulated in the degradation of 4-ABS. When incubated in 50 mM Tris-HCl buffer (pH 8.0) containing 2.2 mM sodium sulfite, strain 624S exhibited no sulfite oxidation; however, strain 624L completely oxidized the sulfite after 2 days. Furthermore, when manganase, which has the ability to oxidize sulfite, was added to the medium, the degradation rate of 4-ABS was increased in comparison with the non-addition control. These results indicate that the sulfite oxidation might stimulate the degradation of 4-ABS by strain 624S, suggesting syntrophic interaction between strains 624S and 624L based on sulfite oxidation.

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

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.

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.

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.

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).