|
|||||
|
|
Structural Alteration of Humic Acids by Pseudomonas spp. from Deep Terrestrial Subsurface Diatomite Formations in Northernmost Japan |
|
| Authors: | Akio Ueno Satoru Shimizu Shuji Tamamura Takeshi Naganuma Yasushi Ohmi Katsuhiko Kaneko |
| Institution: | 1. Horonobe Research Institute for the Subsurface Environment, Northern Advancement Center for Science and Technology, Hokkaido, Japan;2. Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan;3. Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan |
| Abstract: | Bacterial utilization of humic acids (HAs) was examined under aerobic conditions using Pseudomonas spp. from diatomite from a depth of 250 m below ground level in the Horonobe Underground Research Laboratory. HA decolorization and bacterial aggregation were observed during cultivation when an auxiliary carbon source was added. High-performance size-exclusion chromatography showed that high-molecular-weight HAs were produced. Fourier transform infrared spectroscopy indicated that carboxyl groups and polysaccharide-related substances in HAs were eliminated, while aliphatic structural units and amide groups were added to HAs. These results suggested that Pseudomonas spp. utilize and alter the molecular structure of HAs under aerobic conditions caused by the construction of underground facilities. |
| Keywords: | bacterial aggregation decolorization Fourier transform infrared spectroscopy high-performance size-exclusion chromatography humic acid subsurface bacteria |