Ralstonia eutropha同時脫氮及合成PHB最適培養條件之研究
The Best Cultivation Condition of Denitrification and PHB Synthesis Simultaneously from Medium by Ralstonia Eutropha
Date Issued
2005
Date
2005
Author(s)
Huang, Pei-Min
DOI
zh-TW
Abstract
It was verified that Ralstonia eutropha could accumulate a large amount of PHB in cells under the aerobic condition, and PHB is the raw material of plastic which can be decomposed by bacteria. So the aim of this study is to find out the growth condition and characteristic of PHB accumulation by Ralstonia eutropha in anoxic state, and then compare it with living under the aerobic and heterotrophic condition. It’s expected that Ralstonia eutropha can remove the nitrate from the waste water and the sludge which possesses high concentrated PHB can be reused. According to the reason above it’s worthy to do this research.
All experiments proceeded in batch reactor. First of all, we provide hydrogen and discuss the growth of Ralstonia eutropha in anoxic condition without nitrate. And then we find out that nitrate is the only electronic acceptor of Ralstonia eutropha in anoxic condition. In that condition hydrogen can be the energy source of Ralstonia eutropha to promote the growth when the carbon lacks in the liquid. In both anoxic and aerobic conditions, Ralstonia eutropha begins to accumulate PHB in growth phase. Furthermore, reaching the highest content of PHB in cells is in the stationary phase. And then declining the PHB content in cells accompanys the coming of endogenous phase.
In anoxic condition, i also researched PHB accumulation by Ralstonia eutropha in different C/N(5.10.20.25 and 30)、ammonia concentration(100 and 200 mgNH4-N/L) and nitrate concentration(292、397 and 485 mgNO3-N/L). The result reveals the difference of PHB accumulation in cells is obvious under C/N<20. The higher concentration of ammonia will accelerate the growth of Ralstonia eutropha and promote the PHB accumulation in cells apparently. There is also influence of enhancing the PHB accumulation in cells as the concentration of nitrate is promoting.
In the aspect of aerobic condition, the different C/N against the influence of PHB accumulation by Ralstonia eutropha was performed. It was found that the condition of aerobic is similar to anoxic condition. The most important difference between the two conditions is that the PHB accumulation in aerobic condition is higher than that in anoxic condition. Maybe it is the faster growth and higher microorganism concentration that leads to the outcome.
Subjects
PHB
Ralstonia eutropha
脫硝
Denitrification
Type
thesis
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