2001 Fiscal Year Final Research Report Summary
Development of high performance bioreactor system for aerobic microbial degradation of trichloroethylene
| Project/Area Number |
11555222
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
生物・生体工学
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| Research Institution | Kyushu University |
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Principal Investigator |
KAWAKAMI Koei Kyushu University, Graduate School of Engineering, Professor, 大学院・工学研究院, 教授 (70091345)
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| Co-Investigator(Kenkyū-buntansha) |
IJIMA Hiroyuki Kyushu University, Graduate School of Engineering, Associate Professor, 大学院・工学研究院, 助教授 (10274515)
SUYAMA Akiko Towa Science Company, Technical Devision, Researcher, 技術部・研究員
FURUKAWA Kensuke Kyushu University, Graduate School of Agriculture, Professor, 大学院・農学研究院, 教授 (90221556)
ONO Tsutomu Kyushu University, Graduate School of Engineering, Assistant, 大学院・工学研究院, 助手 (30304752)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Trichloroethylene / Bioremediation / Bioreactor / Immobilization / Reactivation / Pseudomonas putida |
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| Research Abstract |
In order to develop a highly efficient bioreactor system for the biodegradation of trichloroethylene (TCE) using agarose gel-entrapped recombinant cells of Pseudomonas putida KF715-D6, we optimized various operating variables for maintaining the activity and stability of the cells over a longer time of degradation. The results derived have been described below :
The degradation temperature was set at 15 ℃ because the highest stability was obtained at this temperature, although the highest activity was appeared at 30 ℃. The optimum reactivating condition was to incubate the cells for 6 h in a basal salt medium (BSM) involving 0.2 mM glucose and 5 mM formate at 4 ℃ and pH 6.5. By reactivating the cells under such a condition, the remaining activity was doubled from 30 % to 60 %, compared with the case of degradation at 30 ℃ without reactivation.
By using the optimized BSM in place of water as the degradation medium, the activity and the stability were increased by 50 % and 10 %, respectively. In addition, it was clarified that the capability of the cells for the TCE degradation was significantly influenced by the cultivation conditions such as shaking speed and cultivation time (the growth phase of cell harvesting). The cells harvested during the exponential growth phase exhibited the highest performance for the viable cell density, initial activity, remaining activity and degradation capacity. However, the cells were harvested at an early stationary phase to obtain a large amount of the biomass. By using BSM as the degradation medium and by reactivating the cells in BSM for 18 h, more than 90 % of the remaining activity was maintained.
Based upon the experimental results described above, a bioreactor system composed of a hydrophobic hollow fiber membrane module for the separation of TCE and a TCE degradation vessel in which the agarose gel-entrapped cells were suspended in BSM, was proposed.
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Research Products
(8 results)
