嗜酸嗜熱細菌之分離及其酯解酵素粗酵素液之性質研究
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Date
2000-06-??
Authors
蔡正國
李銘亮
Journal Title
Journal ISSN
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Publisher
國立臺灣師範大學生命科學學系
Department of Life Science, NTNU
Department of Life Science, NTNU
Abstract
從酸性的溫泉(約pH3、55℃)附近分離出數種細菌。依細菌的特性，其中一種分類為 Bacillus acidocaldarius，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pH4及55℃。以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細菌生長，但是對於酯解酵素的分泌似乎沒有明顯的影響。此酯解酵素作用之最適pH值及溫度分別為中性(pH7)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℃之半生期為30分鐘，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。
Several moderate themlophilic bacterial strains were isolated from hot acid spring about pH 3 and 55℃ by enrichment methods. One of those was identified as Bacillus acidocaldarius. This strain grew undera narrow pH (pH 3~4) and moderate high temperature (45~65℃) condition and was optimal at pH 4 and55℃. A thermostable esterase activity was detected in the culture medium supernatant when assayed 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℃, respectively. This crude esterase activity was found capable of hydrolyzing long-chain fatty acid esters (pNPC 12 to pNPC 16) and exhibited thermal stability. It showed a half-life of 30 min at 75℃, and after 3 h incubation at 95 ℃, 18 % of the activity still remained. The effects of several kinds of salts, detergent, and chelating agent, EDT A 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 effect on it.
Several moderate themlophilic bacterial strains were isolated from hot acid spring about pH 3 and 55℃ by enrichment methods. One of those was identified as Bacillus acidocaldarius. This strain grew undera narrow pH (pH 3~4) and moderate high temperature (45~65℃) condition and was optimal at pH 4 and55℃. A thermostable esterase activity was detected in the culture medium supernatant when assayed 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℃, respectively. This crude esterase activity was found capable of hydrolyzing long-chain fatty acid esters (pNPC 12 to pNPC 16) and exhibited thermal stability. It showed a half-life of 30 min at 75℃, and after 3 h incubation at 95 ℃, 18 % of the activity still remained. The effects of several kinds of salts, detergent, and chelating agent, EDT A 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 effect on it.