- 作者: 蘇遠志; 許清森
- 作者服務機構: 國立臺灣大學農業化學研究所
- 中文摘要:
有些微生物產生之β-吠喃果糖??同時具有蔗糖水解活性與果糖轉移活性,後者可以催化以蔗糖為基質之果糖轉
移反應而合成低聚果糖。作者由台灣土壤中分離篩選得到之Aspergillus japonicus CCRC 38011可以產生多量果糖轉移
活性,具有工業應用之潛力。此菌株在6公升小型醱酵槽中培養時,能產生191.5 units/ml之果糖轉移活性和僅9.9 uni-
ts/ml之蔗糖水解活性,其果糖轉移活性與蔗糖水解活性之比值為19.3;而在1000公升醱酵槽中進行酵素生產之擴大規
模試驗時,可以產生256.1 units/ml之果糖轉移活性和21.1 units/ml之蔗糖水解活性,兩者之比值為12.1。此種酵素極
適合於合成低聚果糖,而不會有明顯之蔗糖水解反應發生,在50% (w/v)蔗糖溶液中反應時,主要之反應產物為低聚果
糖和葡萄糖,而不產生游離之果糖。
大部分之酵素活性存在細胞內,嘗試使用四種處理方式進行酵素之萃取時發現,保溫處理和超音波處理之萃取效果
較佳,其對胞內酵素之萃取效率最高分別為66.3%和44.3%;而均質化處理和冷凍解凍處理並不能有效的使菌體內酵素
釋出。經保溫處理釋出之溶解性酵素,可用丙酮沈澱法回收,對粗酵素溶液添加等體積之丙酮可以沈澱回收溶液中
99.5%之酵素活性,經此操作之酵素純化倍數亦高達15.8倍。
A. japonicus CCRC 38011產生之β-吠喃果糖??之最佳作用pH和溫度分別為5.O和65-70°C,而在pH 4.5至5.0
之間,溫度60°C以下時較為安定。
a - 英文摘要: The fungus (Aspergillus japonicus CCRC 38011) was found to be able to produceβ-fructofuranosidasewith high transfructosylating activity (Ut), a key enzyme involved in synthesis of fructooligosaccharidesfrom sucrose. The Ut productivities of this microorganism were 191.5 units/ml broth in a 6-L jar-fermentorand 256.1 units/ml broth in a 1000-L pilot-fermentor in a modified medium containing 8% sucrose as acarbon source. Most of the Ut of this microorganism was found to be bound with mycelia. Incubation and sonica-tion treatment extracted this enzyme from mycelia with maximum efficiencies of 66.3c% and 44.3%, respec-tively. On the other hand, homogenization and freeze-thawing treatment had only a small effect on enzymeextraction. The soluble enzyme extracted from mycelia by incubation at pH 5.0 and 40°C for 3 hours couldbe easily recovered and purified by acetone precipitation. The recovery of Ut from the crude enzyme solu-tion was 99.5% by mixing the solution with an equal volume of acetone at 4°C, followed by centrifugation.The purification factor of acetone precipitation was 15.8. The optimum pH and temperature of Ut was 5.0 and 65-70°C, respectively. The enzyme was stableat a pH between 4.0 and 5.0 and at a temperature below 60°C.
- 中文關鍵字: β-Fructofuranosidase; Aspergillus japonicus CCRC-38011; transfructosylating activity; fructooligosaccharides.
- 英文關鍵字: --