Toshihiko Ogawa

Degradation of crystal violet by Nocardia corallina

Crystal Violet (BV3), a typical triphenylmethane dye, was degraded by growing cells of Nocardia corallina IAM 12121, although their growth was inhibited at the initial stage of incubation. The dye was degraded at a low concentration, below 5 μmol dm−3. The growth of the cells was completely inhibited at a dye concentration of 7 μmol dm−3. A degradation product of BV3 was identified as 4,4′-bis(dimethylamino) benzophenone (Michlers ketone; MK) by gas chromatography-mass spectrometry. The product was obtained in a reasonable yield since it was not further metabolized by N. corallina IAM 12121.

Degradation of p-Aminoazobenzene byBacillus subtilis

Summaryp-Aminoazobenzene (PAAB) was degradated byBacillus subtilis. Both aniline and p-phenylenediamine as degradative compounds from PAAB were identified by thin layer chromatographic-, and high performance liquid chromatographic-methods. This fact suggests that the first degradative reaction of PAAB byB. subtilis is reductive fission of azo bond in PAAB.

Some properties of azoreductase produced by Pseudomonas cepacia

As for the recent research on azoreductase, (i) the reduction mechanism of azoreductase by hepatic cell-free extracts or rat internal contents, (ii) the spectrophotometric determination for the enzyme by rat hepatic microsome, and (iii) the fluorophotometric determination for rat liver cytosol using Methyl Red as a substrate were studied. There is no research on the purification of the enzyme and also on identification of metabolic intermediates using labelled compounds as substrates. In a previous paper, the microorganism, which degraded p-aminoazobenzene into aniline and p-phenylenediamine was isolated from waste waters of dyestuff industries in the Gifu district, Japan, and also reduction, oxidation and acetylation of p-aminoazobenzene were reported. In this paper, the authors describe partial purification procedure of azoreductase, some properties of the azoreductase and identification of degradative intermediates, p-phenylenediamine and aniline, from p-aminoazobenzene using two types of (/sup 14/C)-labelled p-aminoazobenzenes.

Biodegradation of azo dyes in multistage rotating biological contactor immobilized by assimilating bacteria.

Wastewaters from deing and finishing processes contain a large amount of organic substances such as thickening agents as well as dyes. It is expected to develop a wastewater clarification technology for removing the dyes and the other organic substances in a single operation by use of the dye assimilating bacteria. The model wastewater was treated, by a rotating biological contactor with disk on which Pseudomonas cepacia 13N was immobilized with k-carrageenan gel

Reductive metabolism of aminoazobenzenes by Pseudomonas cepacia

The authors earlier isolated a few strains of microbes in sludge from the sewage of an azo dye factory which had assimilability to azo dye. Among them, strain 13NA was identified as Pseudomonas cepacia based on Bergeys Manual and was named Pseudomonas cepacia 13NA. A model experiment for continuous treatment of dye waste was also reported. Some strain 13NA specificities for aminoazobenzenes and reductive and acetylating pathways are described in the present study.

Influence of chromium compounds on microbial growth and nucleic acid synthesis

The wastewaters of the dyeing and the tanning industry contain often various chromium compounds, e.g. K{sub 2}Cr{sub 2}O{sub 7} and CrCl{sub 3}, with a large quantity of organic substances. Biological treatments have generally been employed in these industrial factories for the biodegradation of organic substances. The toxicity of the chromium compounds have been studied regarding mutagenicity and carcinogenicity from the medical view point. This is also of interest from the view point of wastewater biological treatments. The inhibitory effects of the compounds on the cell growth and the respiration in activated sludge have been reported in detail, but mechanisms have not been sufficiently elucidated. Therefore, the influence of K{sub 2}Cr{sub 2}O{sub 7} and CrCl{sub 3} on the cell growth and on the nucleic acid content was measured. Both compounds were the inhibitors of DNA synthesis. These action resulted in increased generation time a decrease in cell division. Chromium compounds and dyes coexist often in the wastewaters of the dyeing industries. The growth inhibitions of the mixed solution were measured.

MICROBIAL REDUCTION OF AZO DYES BY SEVERAL STRAINS

Abstract The microbial reduction of relatively simple azo dyes was investigated. The reduction in the initial step of the microbial degradation of the dyes was microorganism‐specific or dye‐specific, because the reduction of the dyes was directly dependent not only on the presence of azoreductase in the microorganisms, but on the permeation of the dye molecules into the cells. The cell permeability barrier of the dye molecules was observed for both sulfonated azo dyes and unsulfonated azo dyes. It was also observed that microbial azoreductase exhibit a narrow specificity.

Growth Inhibition of Bacillus subtilis upon Interaction between Basic Dyes and DNA

Wastewater in the process of dyeing is not always purified effectively by biological treatment such as the activated sludge method, since dyes, bichromates, etc. contained in the water are toxic to microbes. In preference to employment of the treatment, therefore, how the components of the water influence growth and physiological activities of microbes should have to be evaluated. It was reported in a previous paper that growth inhibition of cells by dyes results from a lowering of nucleic acid synthesis. In this paper, adsorption isotherms of basic dyes to cells, effects of dyes on melting temperature of DNA and mutagenicity of dyes were measured respectively, and the correlation between these values and cell growth inhibition was investigated. It was found from the results that stabilization of DNA double helix was related closely to cell growth inhibition.

Oxidative pathway after reduction of p-aminoazobenzene by Pseudomonas cepacia

The waste waters of dyestuff industries in Gifu district are applied for mixed treatment with municipal sewage by activated sludge. Toxicities of the dye against microorganisms cause degradation of purifying functions in treatment plants. Therefore, when there is a great deal of waste water from dyestuff industries, primary treatment is required with dye-assimilating bacteria in dyestuff industries. In the soil obtained from the drain trench of dyestuff industries in the Hashima district, a few kinds of dye-assimilating bacteria were isolated and identified. To investigate the possibility of primary treatment with these strains, the metabolic pathways of dyestuffs with such bacteria were studied. In the previous study, p-aminoazobenzene was found to be subject to reductive fission of the azo bond and acetylation of the amino group. In a continuation of the study of the previous metabolites, the authors isolated and identified other metabolites, the authors isolated and identified other metabolites, o-aminophenol, m- and p-acetamidophenol, and 3,4-dihydroxyacetanilide, from the culture broth of Pseudomonas cepacia 13NA. The isolation and identification of these metabolites are reported in the present study.

Degradation of 4′-dimethylaminoazobenzene-2-carboxylic acid by Pseudomonas stutzeri

Abstract4′-Dimethylaminoazobenzene-2-carboxylic acid (DMBC) was utilized as a necessary carbon and nitrogen source by Pseudomonas stutzeri IAM 12097. o-Aminobenzoic acid (o-ABA), N,N-dimethyl-p-phenylenediamine (DMPA) and cathecol were identified as intermediates of DMBC degradation. DMBC was degraded at a concentration below 70 μmol dm−3. The ability to utilize DMBC in P. stutzeri was lost spontaneously to some extent. When P. stutzeri was cured of plasmid DNA (approximately 8 MDal) by treatment with mitomycin C, acridine orange, and chloramphenicol, DMBC was not utilized by the resultant strain. These facts suggest that the degradative ability on DMBC in P. stutzeri is controlled by plasmid DNA.