The University of Osaka · Environmental Science
Professor Michihiko Ike's research lab specializes in environmental biotechnology and microbial ecology, focusing on the biodegradation of emerging organic pollutants such as bisphenols, nonylphenol ethoxylates, and other endocrine-disrupting chemicals in aquatic environments. The lab investigates microbial degradation pathways, isolates and characterizes pollutant-degrading bacteria, and explores the genetic and biochemical mechanisms underlying the transformation of recalcitrant environmental contaminants. A key research direction involves assessing the environmental fate and mineralization potential of these compounds under both aerobic and anaerobic conditions, with applications in pollution control and ecological risk assessment.
Figures are computed from collected data and may differ slightly.
There is a group of compounds structurally similar to bisphenol-A (BPA), namely bisphenols (BPs), and some of them are considered to be able to partially replace BPA. In order to assess their biodegradability in the aquatic environment, a variety of BPs; BPA, bis(4-hydroxyphenyl)methane (BPF), bis(4-hydroxyphenyl)ethane (BPE), 2,2-bis(4-hydroxy-phenyl)butane (BPB), 2,2-bis(4- hydroxy-3-methylphenyl)propane (BPP), bis(4-hydroxyphenyl)sulfone (BPS), thiodiphenol (TDP) and 4,4'-dihydroxybenzophenon
Biodegradation of bisphenol-A (BPA), which is known as an estrogenic chemical, proceeds via complicated metabolic routes and leads to formation of several kinds of biodegradation products. Through the major route BPA can be completely mineralized; however, p-hydroxyacetophenone (p-HAP), p-hydroxybenzaldehyde (p-HBAL), and p-hydroxybenzoic acid (p-HBA) are transiently accumulated at relatively high concentrations. On the other hand, degradation of BPA through the minor route tends to cause the ac
Biodegradation potential of bisphenol A (BPA) in the aquatic environments was investigated using 3 activated sludge and 44 river water microcosms. The biodegradation potential was exhibited by most of the tested microcosms; 3 activated sludge and 40 river water microcosms. However, only 6 river water microcosms could completely mineralize BPA, and the others showed accumulation of common metabolites which were detected as 2 peaks according to a high-pressure liquid chromatograph. In total 19 BPA
Previously, we isolated a selenate- and arsenate-reducing bacterium, designated strain SF-1, from selenium-contaminated sediment and identified it as a novel species, Bacillus selenatarsenatis. B. selenatarsenatis strain SF-1 independently reduces selenate to selenite, arsenate to arsenite, and nitrate to nitrite by anaerobic respiration. To identify the genes involved in selenate reduction, 17 selenate reduction-defective mutant strains were isolated from a mutant library generated by random in
Three bacteria capable of utilizing bis(4-hydroxyphenyl)methane (bisphenol F [BPF]) as the sole carbon source were isolated from river water, and they all belonged to the family Sphingomonadaceae. One of the isolates, designated Sphingobium yanoikuyae strain FM-2, at an initial cell density of 0.01 (optical density at 600 nm) completely degraded 0.5 mM BPF within 9 h without any lag period under inductive conditions. Degradation assays of various bisphenols revealed that the BPF-metabolizing sys
The degradation kinetics of biotransformation products of nonylphenol polyethoxylates (NPEOs), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenoxy carboxylic acid (NP1EC), by ozonation and UV/TiO2 (ultraviolet photocatalytic degradation in the presence of titanium dioxide suspension as a catalyst) were investigated using lab-scale reactors. The degradation rate of NP by UV/TiO2 was the highest among the tested NPEOs metabolites, while NP1EC showed the lowest degradation rate. I
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