以嗜酸性硫氧化細菌作為生物感測器檢測環境汙染物

Using acidophilc sulfur-oxidizing bacterium as biosensor to detect environmental pollutants

楊淳皓(Chun-Hao Yang)

指導教授 ： 廖秀娟

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701310

摘要

近年來，高度的工業發展導致許多環境汙染物排放到環境中，包括重金屬、農藥、新興汙染物等，且已影響世界眾多人口的健康。化學檢測法雖然具有高靈敏度及準確度，然而其價格高以及檢測耗時，難以應用於大規模的樣品篩測。因此本研究利用硫氧化細菌作為生物檢測器檢測環境中的環境汙染物，以期能和現有的化學分析方法互補。本研究於陽明山硫磺谷的土壤中篩選出一株嗜酸性硫氧化菌，並利用環境汙染物的毒性，因而使得在有氧的環境下，抑制硫氧化酵素將元素硫氧化成硫酸的能力，進而造成pH值無法下降及EC值無法上升的原理，建構出以檢測pH值及EC值變化為基礎的生物感測器。本研究篩選出的現地硫氧化菌SV5經16S rDNA定序並鑑定發現其序列與Acidicaldus organivorans strain Y008最為相近，序列相似度達99%。研究結果顯示SV5最佳生長環境為FYM培養基，需大量培養時可加入葡萄糖。最佳生長條件為pH值2.5、溫度37 ℃。此外，菌株SV5雖不能檢測塑化劑 (DEHP)、三唑醇 (triadimenol)，但能檢測超過環保署放流水標準10倍的砷及100倍的鎘，也能檢測環保署放流水標準濃度的鉻，檢測時間為4天。另外本研究也發現六價鉻能有效抑制SV5硫氧化蛋白的活性。總的來說，本研究建構之硫氧化生物感測器具有操作簡單、成本低的優勢，可與化學分析方法進行互補，提升大量篩檢重金屬樣品檢測效率。

關鍵字

生物感測器 ； 重金屬 ； 砷 ； 鎘 ； 鉻 ； 硫氧化細菌 ； 環境汙染物

並列摘要

In recent years, highly industrial development causes many environmental pollutants releasing into the environment, such as heavy metals, agricultural pesticides and emerging contaminants, thereby threaten people’s health around the world. Despite chemical analysis has been proven highly sensitive and accuracy, it still has limitation for large scale screening due to the cost and time consuming. The goal of this study is to use a sulfur-oxidizing bacterium as a biosensor to detect environmental pollutants.in order to current complement chemical analysis. In this study, an acidophilic sulfur-oxidizing bacterium was isolated from the soil of the Sulfur Valley near Yangmingshan. We developed the biosensor based on the bacterium’s sulfur-oxidizing ability to H2SO4 is inhibited by the environmental pollutants toxicity in the presence of O2 and S0, thereby preventing the decrease in pH and the increase in EC. Based on the 16S rDNA sequence analysis, the bacterium SV5 has 99% sequence similarity to Acidicaldus organivorans strain Y008. The optimal growth medium for SV5 is ferrous iron/yeast extract liquid medium (FYM), and the optimal temperature and pH is 37 ℃ and pH 2.5, respectively. The results showed that although SV5 could not effectively detect DEHP and triadimenol, it was able to detect 10-fold EPA effluent standard concentration of arsenic, 100-fold EPA effluent standard concentration of cadmium, and 1-fold EPA effluent standard concentration of chromium in 4 days. Finally, this study demonstrated that chromium inhibits sulfur-oxidizing protein activity of SV5. In conclusion, the sulfur-oxidizing biosensor in this study is easy to operate and cost-effective. It can not only compromise current chemical analysis but also increase the efficiency of large scale screening of environmental pollutants.

並列關鍵字

biosensor ； heavy metal ； arsenic ； cadmium ； chromium ； sulfur-oxidizing bacterium ； environmental pollutants

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