酸性熱泉水中元素硫氧化菌之分離培養與代謝分析

Abstract

摘要 本研究使用元素硫氧化培養基，由陽明山區小油坑池水 （泉溫為 71.6℃，酸鹼值為 2.36）沈積物中，培養並分離出一株元素硫氧化菌 (SYK-ESO-1)，經過16S rDNA鑑定，屬於 Acidianus 屬，與 Acidianus manzaensis strain NA-1 及 Acidianus manzaensis strain TA均有 99% 的相似度。此菌株可生長酸鹼值為 0.0-5.0 之間 (最適酸鹼值為 2)，可生長溫度範圍為 50-85℃ （最適溫度為 82℃），可生長在 0.0-10.0 ‰ 的 NaCl 濃度中（最適NaCl濃度為1.67‰）。細胞為直徑 0.5-2.2μm 的不規則球型。耗氧情況可氧化元素硫自營生長、或使用有機物行異營生長，亦可以有機混合物 (meat peptone、tryptone、yeast extract或starch) 或多醣類 (葡萄糖 (glucose)、蔗糖 (sucrose)、甘露糖 (mannose)、乳糖 (lactose) 、丙酮酸 (pyruvate)) 做為單一碳源。在厭氧條件下，三價鐵、硝酸、亞硝酸、硫酸及元素硫均無法做為電子接受者，以供此菌株生長。此株氧化元素硫生長時，硫酸根的產生在細胞生長延遲期即呈指數上升，到了細胞指數期後半則線性上升，而在高原期維持相同的速率。生長溫度越高，硫酸根產生速率越快；酸鹼值對硫酸根產生影響極大，只在最適酸鹼值的狹小範圍內硫酸根才能大幅產生；而氯化鈉濃度對硫酸根產生速率影響較小，僅在氯化鈉濃度上限 10 ‰ 有產率上升的現象。

Abstract A thermoacidophilic sulfur-oxidizing Archaea, strain SYK-ESO-1, was isolated from a hot spring in Shauyuken （71.6℃, pH 2.36）, Yangminshan. On the basis of 16S rDNA analysis, strain SYK-ESO-1 is affiliated with Acidianus manzaensis strain NA-1 and Acidianus manzaensis strain TA at a similarity of 99 %. The range of growth temperature, pH and NaCl concentration are 50-85℃ (optimum at 82℃), 0.0-5.0 (optimum at pH= 2.0), 0-10 ‰ (optimum at 1.67 ‰), respectively. The cells are irregular cocci. Strain SYK-ESO-1 is aerobic and can grow autotrophically using S0 as an electron donor and heterotrophically using some organic compounds. Fe3+, NO3-, NO2-, SO42- and S0 do not serve as electron acceptor under anaerobic condition. When the strain lives on sulfur oxidation, sulfate production increases exponentially, while cell growth is still in lag phase. While the growth is in log phase, sulfate production increases linearly. Sulfate production rates also elevate with the increase of temperature. Cells produce sulfate only in a narrow range around optimum pH. The influence of NaCl concentration on sulfate production rate is minor, and sulfate production rate raises only in upper limit concetraction 10 ‰.