| 摘要: | 本研究在測試台灣本土固有菌種脫氯能力，研究分為兩部分：(1)多氯聯苯(Polychlorinated biphenyls,PCBs)脫氯實驗：採集二仁溪十點，(2)六氯苯(Hexachlorobenzene,HCB)脫氯實驗：採集二仁溪、後勁溪中下游各一點，共四點。於二仁溪十點分別萃取出天然的底泥水加入yeast extract 5g/l作為培養基，並添加2,3,4-CBp，而底泥微生物在90天後開始脫氯，未添加yeast extract 則在160天後仍無明顯的脫氯情形；而另外再添加人工培養基和yeast extract 5g/l，顯示十點皆有50-90天的遲滯期，在遲滯期後50天完全脫氯；加已馴化的微生物則有18-24天的遲滯期，在12天後完全脫氯。另
外，於二仁溪、後勁溪中下游各分別萃取出天然的底泥水加入yeast extract 5g/l，並添加HCB，顯示在60天後開始脫氯，無添加yeast extract只有兩點有脫氯情形；而另外再添加人工培養基和yeast extract 5g/l，顯示四點皆有45-60天的遲滯期，在遲滯期後30天完全脫氯。在脫氯的過程中，皆伴隨著甲烷產生和氧化還原電位的(ORP)的下降。綜合以上結果顯示，在台灣河川底泥中原有的微生物有使六氯苯和多氯聯苯脫氯的能力，且若添加營養源，能促進微生物脫氯的能力。
In order, to test the inherent polychlorinated biphenyls(PCBs) and hexachlorobenzene(HCB) dchlorination ability of indigenous consortia in southern Taiwan , microorganisms from ten sites of Erh-Jen river and two sites of Ho-Tsin river were collected and applied to dechlorination experiment.
In PCBs dechlorination experiments, by using natural sediment-extract
waters as culture medium, when adding with 5g/L of yeast extract, all ten sets of
sediment microorganisms initiated 2,3,4-CBp dechlorination after 90 days.
Without yeast extract, no set showed dechlorination ability during a period of
160-days incubation. However, in the artificial synthetic media amended with
5g/L of yeast extract, all microbes from ten sediments showed
PCBs-dechlorinating activity after 50~90 days of lag phases and completed
dechlorination with latter 50 days. The acclimated microorganisms of all ten
sets dechlorinated 2,3,4-CBp effectively within a short lag phase of 18~24 days,
and the transformation completed within another 12 days of incubation.
In HCB dechlorination experiments, by using natural sediment-extracted waters as media, when amended with 5g/L of yeast extract , all four sets of sediment microorganisms initiated HCB dechlorination after 60 days. Without yeast extract , there were only two sets of microbes dechlorinated HCB during a 150-day incubation period. On the other hand, in the artificial synthetic media amended with 5g/L of yeast extract , all microbes from four sediments showed HCB-dechlorinating activity after 45-60 days of lag phases and completed dechlorination in latter 30 days. In all HCB-dechlorinaed sets, dechlorination was accompanied by significant methane generation and the drop of oxidation-reduction potential (ORP).
The results indicated that there were HCB- and PCBs-dechlorinating consortia grouped by the indigenous microorganisms in the river sediments of southern Taiwan, even though these sediments had not been contaminated by HCB and PCBs before. Therefore, the dechlorination could occur when the environmental conditions were suitable for the dechlorinating consortia to be enriched, and then the ability for HCB and PCBs decomposition was built up. |
