Yonekichi Sakurai

Microbial oxidation of arsenite and occurrence of arsenite‐oxidizing bacteria in acid mine water from a sulfur‐pyrite mine

Abstract The acid mine waters (pH 2.0–2.4) discharged from the Matsuo sul‐fur‐pyrite mine contained high concentrations of dissolved inorganic arsenic (2–13 ppm). Arsenic in the superficial acid mine waters was predominantly in the (V) state (arsenate); however, the element in the water from a deep mine drift was almost in the (III) state (arsenite). Microbial arsenite oxidation occurred in the acid mine waters and along the stream of the river, which was contaminated with a large volume of the mine drift water. Arsenite (500 ppm As)‐resistant bacteria (0–27 colonies/ml) were detected in the water samples and 208 slant cultures were obtained. Arsenite‐oxidizing activities of all the cultures were determined and six strains with strong arsenite‐oxidizing activity were isolated. These bacteria were acidophilic (optimum growth pH, 3—4), gram‐negative, aerobic, and rod‐shaped. They could not oxidize ferrous iron and elemental sulfur as a sole energy source and not derive the energy for chemoautotrophic growth...

Distribution of bacteriochlorophylla in species of the genusAcidiphilium

Bacteriochlorophyll (Bchl)a was found in strains of the strictly aerobic acidophilic heterotrophic bacteria:Acidiphilium rubrum, A. angustum, andA. cryptum. Absorption spectra of the cell-free extracts showed a large peak at 865 nm and a small peak around 802 nm. Anaerobic growth was not observed in either the light or the dark. Bchla was not detected in eitherA. organovorum orA. facilis. Bchla contents were less than ca. 0.7 nmol/mg dry cell weight, being variable among the species.

Effects of the Amino-Carbonyl Reaction of Ribose and Glycine on the Formation of the 2(or 5)-Ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone Aroma Component Specific to Miso by Halo-Tolerant Yeast

The formation of HEMF[2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone], the aroma component specific to miso and soy sauce, was promoted by cultivating the halo-tolerant yeast, Zygosaccharomyces rouxii, in a medium including the amino-carbonyl reaction products based on ribose and glycine. The glucose concentration in the medium influenced the HEMF formation by Z. rouxii.

SEASONAL VARIATIONS IN NUMBER OF ACIDOPHILIC IRON-OXIDIZING BACTERIA AND IRON OXIDATION IN THE RIVER CONTAMINATED WITH ACID MINE WATER

Abstract Number of acidophilic iron-oxidizing bacteria, soluble iron, pH, and water temperature were measured seasonally at five sampling stations in the Akagawa River which is highly polluted by strongly acid mine water discharged from the abandoned Matsuo sulfur and iron-sulfide mine area. Other environmental variables of the river water were also determined (titratable acidity. dissolved oxygen, electrical conductivity, sulfate, aluminum, ammonia and nitrate-nitrogen, and phosphate). Distinct seasonal variations in the number of iron-oxidizing bacteria and ferric iron concentration were observed of the river water during the flow and were correlated with seasonal change in water temperature. Hydrogen ion concentration, dissolved oxygen, nutrients for microorganisms, such as, nitrogen and phosphate in the water of the main stream were judged to be not limited to iron oxidation or bacterial growth. Thus, water temperature was found to be a major environmental factor influencing on the activity of iron ox...

Microbial oxidation of ferrous iron in acid mine water at sulfur and iron-sulfide mine

Abstract The microbial oxidation of ferrous iron in the acid mine water from the abandoned Matsuo sulfur and iron-sulfide mine area was investigated. The acid mine water had an extremely low pH value and contained a high concentration of ferrous iron (about 1,000 ppm). The ferrous iron was oxidized rapidly to the ferric form in the acid mine water. The oxidation of ferrous iron in the acid mine water was completely inhibited by millipore filtration, toluene addition or incubation at a low temperature. These facts indicate that the oxidation of ferrous iron is not a spotaneous oxidation by atmospheric oxygen but a biological oxidation. Iron-oxidizing bacteria were ubiquitously found in the acid mine water samples taken from the mine area. The number of iron-oxidizing bacteria and the iron oxidation ratio along the Akagawa River were found to increase gradually as the stream ran down. The degree of iron oxidation was well correlated with the number of iron-oxidizing bacteria. From these results it is conclu...

Distribution of acidophilic iron- and sulphur-oxidizing bacteria in a sulphur and iron sulphide mine

Abstract The numbers of acidophilic iron- and sulphur-oxidizing chemolithotrophic bacteria, as well as certain physical and chemical environmental factors, were examined in weathered iron sulphide ores and acid mine drainage waters at the abandoned Matsuo sulphur and iron sulphide mine in Japan. In the ores, the population of iron-oxidizing bacteria was smaller than that of sulphur-oxidizing bacteria. On the other hand, an inverse relationship between iron- and sulphur-oxidizing bacteria was observed in the acid mine waters. The marked differences between the ores and acid mine waters in their numbers of iron- and sulphur-oxidizing bacteria, may reflect the availability and content of the respective energy sources: ferrous iron and elemental sulphur.