| Project/Area Number |
17310042
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Environmental technology/Environmental materials
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
TANAKA Hideo University of Tsukuba, Professor Emeritus (40015657)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
AOYAGI Hideki University of Tsukuba, Graduate School of Life and Environmental Sciences, Associate Professor (00251025)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥15,660,000 (Direct Cost: ¥15,000,000、Indirect Cost: ¥660,000)
Fiscal Year 2007: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2006: ¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 2005: ¥7,000,000 (Direct Cost: ¥7,000,000)
|
|---|
| Keywords | symbiosis / Chlorella / chemical communication / physical communication / sheath / Extracellular released organic carbon / mixed culture / waste water treatment / 複合微生物系 / レクチン / 複合生物系 |
|---|
| Research Abstract |
Chlorella sorokiniana IAM C-212 has long been maintained in slant culture as a mixed strain, representing an associated natural microbial consortium. The consortium was separated and four nonalgal constituents, a fungal strain (Acremonium sp.), and three bacterial strains (Ralstonia pickettii, Sphingomonas sp. DD38, Microbacterium trichotecenolyticum) were isolated and identified. The interaction between Chlorella and its symbionts under photoautotrophic conditions involved both mutualism and commensalisms. Sphingomonas sp. And M. trichotecenolyticum were harbored on the sheath produced by Chlorella, while Acremonium sp. And R. pickettii directly adhered to the Chlorella cell surface by using lectin-like substances. The sheath is composed of sugars, amino acids, vitamins and metals. A novel artificial medium that imitates photoautotroph-heterotroph interaction was developed. With the artificial medium, it was possible to selectively isolate some novel bacterial strains. The sheath is a suitable habitat for several symbiotic microorganisms because it ensures close proximity between the C. sorokiniana and symbionts. The sheath was increased by addition of calcium chloride. The sheath resulted in coflocculation of C. sorokiniana and the associated symbiotic bacteria, thus strengthening the bacterial-Chlorella symbiotic association. An application of this technique was demonstrated by constructing a complex of C. sorokiniana and a propionate-degrading bacterium (PDS1). Although propionate inhibited the growth of axenic C. sorokiniana, the C. sorokiniana-PDS1 complex (CPC) showed good growth in a medium containing a high concentration of propionate. The CPC was also used for simultaneous removal of organic acids, nitrate, ammonia and phosphate.
|
