PubMed Health⌕ Search

Biomedical subjects

M Shoda

Publications and source records attributed to M Shoda.

At least 91 records · Page 5Linked to original sources
PubMed1985

Change in Microbial Numbers during Thermophilic Composting of Sewage Sludge with Reference to CO(2) Evolution Rate.

Dewatered sewage sludge was composted in a laboratory-scale autothermal reactor in which a constant temperature of 60 degrees C was kept as long as possible by regulating the air feed rate. The change in CO(2) evolution rate was measured continuously from the start up through the cessation of compositing. The succession of mesophilic bacteria, thermophilic bacteria, and thermophilic actinomycetes was also observed during the composting. Specific CO(2) evolution rates of thermophilic bacteria and actinomycetes in the constant-temperature region of 60 degrees C were assessed quantitatively. It was found that the CO(2) evolution rate was attributed to thermophilic bacteria at the initial stage of 60 degrees C and to thermophilic actinomycetes at the later stage of 60 degrees C.

Journal Article↗
PubMed1985

Characteristics of Mesophilic Bacteria Isolated during Thermophilic Composting of Sewage Sludge.

The degree of inactivation by UV irradiation was different between vegetative cells and spores of bacteria isolated from sewage sludge composting at 60 degrees C. By using this property, a method to estimate the spore ratio of a mixture of vegetative cells and spores was presented. This UV irradiation method was applied to the estimation of the spore ratio of sewage sludge compost samples collected at several stages of composting. The spore ratio of mesophilic bacteria in the samples obtained at the thermophilic stage of 60 degrees C was 40% at most. The vegetative form of mesophilic bacteria showed a thermotolerance property at 60 degrees C by forming colonies but showed no respiratory activity at that temperature.

Journal Article↗
PubMed1985

Effect of seeding during thermophilic composting of sewage sludge.

The effect of seeding on the thermophilic composting of sewage sludge was examined by measuring the changes in CO2 evolution rates and microbial numbers. Although the succession of thermophilic bacteria and thermophilic actinomycetes clearly reflected the effect of seeding, no clear difference was observed in the overall rate of composting or quality of the composted product.

Bacteria↗
PubMed1985

Effect of temperature on composting of sewage sludge.

The effect of temperature on the composting reaction of sewage sludge was investigated at 50, 60, and 70 degrees C. The total amount of CO(2) evolved and the final conversion of volatile matter were maximum at 60 degrees C., suggesting that the optimal temperature for composting was around 60 degrees C. The specific CO(2) evolution rate (moles of CO(2) evolved per hour per viable cell) was maximum at 70 degrees C. The isolated thermophilic bacterium which was dominant at 60 degrees C but did not grow at 70 degrees C showed that the rate of O(2) consumption measured on the agar plate at 70 degrees C was four times higher than that at 60 degrees C. This showed that the energy yielded from catabolism is rather uncoupled with the anabolism at 70 degrees C in the metabolism of microorganisms indigenous in the compost. A higher respiratory quotient was observed at 70 degrees C than at any other temperature.

Journal Article↗
PubMed1980

Preferential utilization of phenol rather than glucose by Trichosporon cutaneum possessing a partially constitutive catechol 1,2-oxygenase.

A phenol-utilizing yeast, Trichosporon cutaneum POB 14, which has a partially constitutive activity of catechol 1,2-oxygenase, utilized phenol in preference to glucose in a medium containing both phenol (200 mg/liter) and glucose (0.15%) as carbon sources. The glucose consumption was not observed until the concentration of phenol decreased to around 10 mg/liter. This phenomenon was confirmed by [U-14C]glucose uptake experiments. The intracellular activities of hexokinase (EC 2.7.1.1) and catechol 1,2-oxygenase (EC 1.13.1.1) changed inversely when phenol was added during growth in the glucose medium.

Biological Transport, Active↗