超嗜热古菌耐热酸性α-淀粉酶的发酵条件和酶学性质研究  

PRODUCTION AND CHARACTERIZATION OF THERMOSTABLE AND ACID-STABLE α-AMYLASE FROM HYPERTHERMOPHILIC ARCHAEON THERMOCOCCUS SP.

作　　者：王淑军[1,2] 陆兆新[1] 秦松[3] 吕明生[2] 李富超[3] 刘红飞[2] 邓祥元[3] 

机构地区：[1]南京农业大学食品科技学院,南京210095 [2]江苏省海洋生物技术重点建设实验室淮海工学院,连云港222005 [3]中国科学院海洋研究所,青岛266071

出　　处：《海洋与湖沼》2009年第1期19-26,共8页Oceanologia Et Limnologia Sinica

基　　金：江苏省“六大人才高峰”第三批资助项目:06-A-017号;江苏省教育厅自然科学基金项目：06KJB550004号;江苏省海洋生物技术重点建设实验室项目:2006HS008号;连云港市自然科学基金项目：KK06076号

摘　　要：对一株分离自深海热液口的超嗜热古菌(Thermococcus sp.HJ21)菌株进行了α-淀粉酶发酵条件的优化和酶学性质的研究。该菌株发酵9h后到达产酶高峰,产酶温度范围为60—90℃,其最适产酶温度为80℃。产酶pH范围为5.0—9.0,最适产酶pH为7.5。产酶NaCl浓度范围为0.5%—4.0%,2.5%为最适宜NaCl浓度。糖原、淀粉、麦芽糖、酵母膏和蛋白胨促进产酶。该菌株产生的α-淀粉酶的分子量为51.4kDa,酶的最适作用温度为95℃,在100℃仍有60%的酶活力。酶在90℃的半衰期为5h,在100℃2h仍有40%的残余酶活,酶的热稳定性不依赖Ca2+。酶的最适作用pH为5.0,pH4.5仍有80%的酶活力,pH在5.5—7.0较稳定(80℃4h)。金属离子1mmol/L的Mg2+、Co2+、Sr2+、Ba2+、K+、Na+对酶有激活作用,Cu2+、Pb2+、Hg2+、Zn2+、Al3+对该酶均有抑制作用。The production and characterization of a-amylase from Thermococcus sp. HJ21 are studied. The maximum enzyme production is achieved after 9 h cultivation. The ranges and the best points of a-amylase production are 60--90℃, 80℃; 5.0--9.0, 7.5 in pH; and 0.5%--4.0%, 2.5% for NaC1 concentration, respectively. The result shows that adding yeast extract, peptone, glycogen, starch, and maltose could enhance the enzyme production, and the strain HJ21 could produce extracellular thermostable and acid-stable a-amylase. In addition, the molecular weight of the enzyme is estimated 51.4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The maximal activity of a-amylase occurs at 95℃; the half-life of the enzyme is 5 h at 90℃; and over 40% of them remain active 2 h after incubation at 100℃. Meanwhile, no Ca^2＋ is required for thermostability. The enzyme remain stable in a wide pH range of 5.5 to 7.0 （at 80℃ 4 h）, and best in 4.5--5.0. Moreover, the enzyme can be activated by Mg^2＋, Co^2＋, Sr^2＋, Ba^2＋, K^＋, and Na^＋, and inhibited by Cu^2＋, Pb^2＋, Hg^2＋, Zn^2＋, and Al^3＋.

关 键 词：超嗜热古菌 热球菌属 Α-淀粉酶 产酶条件 酶学性质 

分 类 号：TQ925[轻工技术与工程—发酵工程]