在本研究中我們藉由液相搖瓶實驗的操作,利用由受柴油污染土壤所篩出的菌株Rhodococcus globerulus H425-2及Nocardia corynebacterioides L29-2,在對柴油主要組成成分中的直烷類及異烷類(分別以正十五烷及異十九烷為代表)進行降解時, 探討Tween系列非離子型界面活性劑的存在與否,對菌株降解碳源之影響。 結果發現在Tween系列界面活性劑中,高HLB值的Tween 20與Tween 40對Nocardia corynebacterioides L29-2生長造成嚴重的抑制,Tween 60在生長初期的前12小時造成抑制,只有低HLB值且疏水基含烯鍵的Tween 80不會抑制菌株生長,且可幫助Nocardia corynebacterioides L29-2降解異十九烷。由探討Tween 80濃度對Nocardia corynebacterioides L29-2降解異十九烷之影響的實驗中,我們推測當添加的Tween 80濃度越高,對異十九烷的溶解及分散度越好,所以異十九烷降解量也隨之增高。 在探討Tween 80對單一菌株降解單一碳源的影響方面:Tween 80可幫助Nocardia corynebacterioides L29-2降解正十五烷(n-pentadecane,C15)及異十九烷(pristane,C19),也可幫助Rhodococcus globerulus H425-2降解異十九烷,但卻可能會被Rhodococcus globerulus H425-2當作部分碳源使用,因而抑制正十五烷之降解。 在混合菌株降解混合碳源的實驗中,Tween 80的存在無法有效幫助等比例混合菌株降解正十五烷及異十九烷,當改變混合菌株比例,使Nocardia corynebacterioides L29-2在混合菌相中佔有較高比例時,Tween 80的添加才可有效促進正十五烷及異十九烷之降解。由此可知,界面活性劑的添加,在混合污染源與混合菌種的系統中,其促進效果將隨菌種比例之不同而有所差異。
This study aimed to study how surfactants affected the biodegradation of oil spill. Tween series surfactants were used to enhance the biodegradation of n-pentadecane and pristane. The effect of Tween on two bacteria, Rhodococcus globreulus and Nocardia corynebacterioides were examined. Nocardia corynebacterioides is capable of degradation both of straight and branched alkanes, but Rhodococcus globerulus can only mineralize normal alkanes. The biodegradation of pristane by Nocardia corynebacterioides was previously found to be inhibited by the presence of n-alkanes. The co-culture of these two bacteria was found to release Nocardia corynebacterioides from the inhibition. Among Tween 20, 40, 60 and 80, Tween 80 was found harmless to the bacteria and the addition of Tween 80 was found to enhance the biodegradation of n-pentadecane and pristane by Nocardia corynebacterioides. However, the presence of Tween 80 seemed to inhibited Rhodococcus globerulus from degrading n-pentadecane. It snowed no advantage to add Tween 80 to the 1:1 co-culture of these two microbes. The biodegradation of neither n-pentadecane nor pristane was enhanced. The enhancement of Tween 80 was more obvious only when Nocardia corynebacterioides became the dominant species in the culture.