Summary. p-Aminoazobenzene (PAAB) was degradated by Bacillus 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 by B. subtilis is reductive fission of azo bond in PAAB.PAAB has been used as one of dispersing dyestuffs in dyeing industry. Recently, it has become known that many dyestuffs cause environmental pollution due to their resistance against biodegradation. PAAB can also be said to be in this category; moreover, it is found that PAAB is not only hardly degradated by activated sludge, but also decreases the activity of activated sludge. Because of this, PAAB must be degradated by some special microorganism.In discussing the metabolism of azo compounds by mammals, it has been reported by (Fours et al., 1957;Daniel, 1962; and West66, 1965) that azo compounds were reductively cleaved. On the other hand, the metabolism of azo compounds by microorganisms has only been studied using brewer's yeast (Eisenbrand and Klauck, 1955), baker's yeast (Mecke and Schm~ihl, 1957) and Proteus vulgaris from intestines of rats (Roxon et al., 1966;1967). In screening the activity of bacteria to degradate PAAB, we found that B. subtilis degradated PAAB faster and stronger than other bacteria examined.In this paper, degradative conditions of PAAB by B. subtilis, isolation, identification of aniline and p-phenylenediamine as degradative compounds from PAAB by thin layer chromatographic-, and high performance liquid chromatographic-methods, and preparation of cell-free extract having PAAB reductase activity from B. subtilis are reported.
Materials and MethodsCbemicals. All chemicals used in this work were commercial products.
Xylose isomerase, an enzyme isomerizing xylose to xylulose, was produced adaptively when Can dida utilis, a fodder yeast, was grown in a medium containing xylose. This experiment was carried out in order to isolate and purify the enzyme, and to clarify properties of the enzyme. As a result, it was revealed that the enzyme could be solubilized by plasmolysis, and was purified by dialysis, salting out with ammonium sulfate, precipitating with acetone, and adsorbing to calcium phosphate gel. The enzyme requires some divalent metal ions for its action and among them manganese ion is the most effective. The enzyme is inhibited particularly by ethylenediamine-tetraacetic acid and has somewhat thermotolerant character.
A bacterium which has the ability to degrade azo dyes has been isolated from a polluted environment and identified as Aeromonas hydrophilia. The specificity of azo dyes to the bacterium was examined. p‐Acetamidoazobenzene, p‐aminoazobenzene, acetanilide, aniline and p‐phenylenediamine, which are produced as metabolites, were also isolated.
A potassium chromate-tolerant bacterium was isolated from activated sludge, and the bacterium was identified as Pseudomonas ambigua G-1. The bacterium tolerated up to 2000 ppm of Cr6+, 1700 ppm of Cu2+ and 200 ppm of Cd2+, but did not tolerate Hg2+. Chemi cal analysis indicated 86.5 % uptake in the soluble fraction and 13.5 % uptake in the insoluble fraction of cells. Chromate uptake distribution in the soluble fraction indicated 28.9 in microsomal fraction and 78.1 % in supernatant fraction, Chromate distribution in the insoluble fraction showed 61 % in lipid-fraction and 21 % in polyphosphate-polysaccharidefraction. Chromate inhibited the syntheses of protein, DNA in soluble fraction and RNA in microsomal fraction.
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