嗜酸嗜熱細菌之分離及其酯解酵素性質之研究

Partial characterization of a novel extracellular thermostable esterase from newly isolated thermoacidophilic Bacillus acidocaldarius strain A1

蔡正國(G. K. Tasi)

指導教授 ： 李銘亮

國立臺灣師範大學/理學院/生物學系/碩士(1999年)

摘要

嗜酸嗜熱細菌之分離及其酯解酵素性質之研究
從酸性的溫泉(約pH 3、55℃)附近已分離出數種細菌。依細菌的特性，其中一種鑑定為Bacillus acidocaldarius，編號為菌株A1，可生長於pH 3~4及45~65℃的培養條件下，生長最適pH及溫度分別是pH 4及55℃。以對硝基酚脂(p-nitrophenyl ester)為受質，可於培養細菌的上清液中偵測到酯解酵素(esterase)的活性。橄欖油的添加雖然可促進A1菌株生長，但是對於酯解酵素的分泌似乎並沒有明顯的影響。此酯解酵素作用之最適pH值及溫度分別為中性(pH 7)及75℃。此酯解酵素可分解長碳鏈的酯質受質(pNPC12-pNPC16)，亦具有相當之熱穩定性，於75℃需處理30分鐘才能去掉一半之活性，而以95℃處理3小時後仍保留有18﹪的活性。也測試了一些鹽類、清潔劑及金屬螯合劑EDTA對此酵素的影響，尚未找到可以促進該酯解酵素活性的離子；然而，清潔劑及某些離子則對酵素活性具有抑制的作用；另外，EDTA的添加不對酵素活性有所抑制。

關鍵字

嗜酸嗜熱菌 ； 熱穩定 ； 酯解酵素 ； HASH(0x8cc0ba4)

並列摘要

ABSTRAT
Partial characterization of a novel extracellular thermostable esterase from newly isolated thermoacidophilic Bacillus acidocaldarius strain A1
Several moderate thermophilic bacterial strains were isolated from hot acid spring about pH 3 and 55 degree C by enrichment methods. One of those was identified as Bacillus acidocaldarius strain A1. This strain grew under a narrow pH (pH 3~4) and moderate high temperature (45~65 degree C) condition and was optimal at pH 4 and 55 degree C. A thermostable esterase activity was detected in the culture medium supernatant when assayed by using the p-nitrophenyl ester. Adding olive oil to culture medium promoted bacterial growth, but had no effects on the esterase activity. The pH and temperature optima for the esterase activity were pH 7 and 75 degree C, respectively. This crude esterase activity was found capable of hydrolyzing long-chain fatty acid esters (pNPC12 to pNPC16) and exhibited thermal stability. It showed a half-life of 30 min at 75 degree C, and after 3 h incubation at 95 degree C, 18﹪of activity still remained. The effects of several kinds of salts, detergent, and chelating agent, EDTA were also examined. No ions used could promote the esterase activity. However, some detergents and ions had inhibitory effects on the enzyme, and EDTA had no inhibitory effects on it.

並列關鍵字

thermoacidophile ； Bacillus acidocaldarius ； thermostable ； esterase

參考文獻

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