土壤中에 있는 phenol分解細菌의 分離·同定 및 phenol分解能에 關한 考察 = Isolation and Identification of Phenol-degrading Bacteria from Soil and Phenol-degradabilities

국문 초록 (Abstract)

Phenol은 有毒性이고 分解되기 어려운 環境汚染物質이며 大部分 芳香族化合物의 中間代謝産物이다. 또한 各種 産業工程에서 高濃度로 排出되기 때문에 그 毒性으로 인해 處理時 問題를 일으키므로, phenol 廢水處理를 위하여, phenol을 sole carbon source로 利用하는 菌株를 土壤으로부터 分離하여, 그 形態學的·生化學的 特性에 의해 同定하였으며, 各 分離菌株의 溫度別 phenol分解能을 比較하여, 優秀菌株에 대하여 phenol濃度別 分解試驗을 實施하였고, 活性汚泥法으로 phenol廢水를 處理하여 다음과 같은 結果를 얻었다.
1. 18個 地域의 土壤試料中 4個 地域의 土壤으로부터 6株의 phenol分解細菌이 分離되었으며 모두 Pseudomonas屬이었다.
2. 初期 phenol濃度를 500mg/ℓ로 하여 溫度別 分解試驗을 한 結果, Strain Ⅰ,Ⅱ,Ⅲ는 30˚C에서 Strain Ⅳ, Ⅵ는 25˚C에서, Strain Ⅴ는 37˚C에서 各各 最高分解率을 나타내었다. 그 中 分解能이 가장 秀麗한 菌株는 Strain Ⅲ로, 20∼37˚C에서 높은 分解率을 나타내었으며, 특히 30˚C에서는 36時間後 99%가 分解되었다.
3. Strain Ⅲ에 의한 phenol濃度別 分解試驗結果, 10,50,100,200,500mg/ℓ의 境遇는 各各 3,6,12,24,36時間에 99%가 分解되었다. 1,000mg/ℓ以上에서는 顯著한 lag phase가 있었으나, 1,000mg/ℓ의 境遇 66時間後 99%가, 2,000mg/ℓ의 境遇 108時間後 98%가 分解되었다. 그러므로, Strain Ⅲ는 비록 分解에 長時間을 要하나 2,000mg/ℓ의phenol도 sole carbon source로 分解可能한 高活性菌株였다.
4. 順應活性汚泥를 利用하여, 100~800mg/ℓ의 phenol廢水를 處理한 結果, 滯留時間을 平均 28時間으로 하여 好條件에서 平均 99.9% 處理되었다.

다국어 초록 (Multilingual Abstract)

Bacteria that can degrade the toxic and persistent pollutant, phenol, were isolated from soil and identified. Their phenol-degradabilities at various temperatures were compared, superior strain was selected and its phenol-degrading activity was tested at various concentrations of phenol. Phenol-wastewater was treated with acclimated and activated sludge.
The results are as follows:
1. Six phenol-degrading bacteria were isolated from four of eighteen soil samples and all of them were identified as genus Pseudomonas by morpho-logical and biochemical characteristics.
2. Optimum temperature of Strain Ⅰ, Strain Ⅱ, and Strain Ⅲ was 30˚C, Strain Ⅳ and Strain Ⅵ was 25˚C and Strain Ⅴ was 37˚C. Of them, Strain Ⅲ had superior degradability at wide temperature range, 20~37˚C, especially, at 30˚C, Strain Ⅲ could degrade 99% of initial phenol 500mg/ℓ after 36 hours.
3. From the test of phenol-degrading activity of Strain Ⅲ at various concentrations of phenol, Strain Ⅲ was highly active strain capable of degrading phenol 2,000mg/ℓ as a sole carbon source, although it took a long time to do.
4. Phenol removal rate in the acclimated and activated sludge reactor fed phenol at 100~800mg/ℓ and operated with retention time of 28 hours in the optimum conditions was 99.9%.