百里酚對304不銹鋼表面微生物腐蝕行為之影響──以淡水河菌種為例

EVALUATION OF THYMOL AS A BIOCIDE AGAINST MICCROBIOLOGICALLU INFLUENCED CORROSION: TAKING TAMSUI RIVER BACTERIA STRAINS AS EXAMPLE

傳統防汙塗料中所使用的殺菌劑如氧化三丁錫（TBTO）雖可有效抑制船身因藻類等生物附著所導致的破壞，但其毒性對海洋生態卻有極大的影響。為了減緩環境中的重金屬汙染及降低海洋生物的毒性危害，本研究將探討環保型殺菌劑應用的可能性。實驗中將採用低毒性的百里酚（Thymol）作為殺菌劑並探討其抑制微生物腐蝕之能力。本研究中所使用菌種為淡水河流域現地採樣篩6隻代表性菌種。實驗中利用微生物學原理檢測殺菌劑之抑菌性：以波長600nm測吸光值，將預活化後之菌培養在含不同濃度的百里酚下，將24小時內的生長趨勢繪成曲線，可得百里酚最小抑制濃度為125ppm；利用電化學試驗判斷細菌附著、生物膜形成情形及百里酚抗菌能力，由動電位極化結果得知百里酚有良好的抑菌效果；利用光學顯微鏡、掃描電子顯微鏡及倒立雷射共軛焦顯微鏡確認底材表面形貌，透過顯微鏡能直接得知細菌附著、生物膜形成之情況及細菌附著導致底材腐蝕型態，並且驗證百里酚具有良好的抗菌能力及抗蝕性質。

This work reports the antibacterial properties and corrosion inhibition effect of a low-toxic alternative biocide, Thymol, on a 304 stainless steel substrate immersed in cultured medium containing marine bacteria. The marine bacteria strains used in this study were isolated from the rust layer of ship hull in the Tamsui River basin, Taiwan. Optical density at 600 nm (OD600) results reveals the minimum inhibition concentration of Thymol for marine bacteria strains is 125 ppm. The OM and CLSM images after 336 h of immersion in the cultured medium with Tyhmol suggested that the biofilm formation was sparse and a large number of dead cells appeared on surface of 304 SS samples. In addition, the corrosion current density and current densities in the anodic region were lower in the presence of Thymol in the marine bacteria strains-inoculated medium.