| 南极微球菌产低温淀粉酶条件优化及酶学性质初步研究 |
| 摘要点击 1281 全文点击 1196 投稿时间：2008-10-17 修订日期：2008-12-16 |
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| 中文关键词 Micrococcus antarcticus 低温淀粉酶 产酶条件 酶学性质 |
| 英文关键词 Micrococcus antarcticus cold-adapted amylase fermentation conditions enzymatic properties |
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| 中文摘要 |
| 采用单因素试验对南极微球菌（Micrococcus antarcticus）产低温淀粉酶的条件进行了初步优化，其发酵培养基组成为（g/L）：Na2HPO4 2.0，KH2PO4 1.0，MgSO4·7H2O 0.1，NaCl 5.0，(NH4)2SO4 2.5，麦芽糖5.0，微量元素溶液5.0 mL，pH 8.0，500 mL三角瓶装液100 mL，12℃，160 r/min振荡培养64 h，在此条件下，发酵液酶活由优化前的0.24 U/mL提高到2.6 U/mL，是优化前的10.8倍.发酵液经Millipore超滤膜包浓缩、Hitrap Q阴离子交换层析、Superdex 200凝胶过滤层析纯化获得纯淀粉酶.该淀粉酶的最适作用温度为30℃，在10～15℃下仍具有较高活性，但对热敏感，属典型的低温酶；最适作用pH为6.0，在pH 6.0～10.0范围内较稳定（＞70%）；Ca2+、Mn2+、Co2+、Mg2+对该酶有较为明显的激活作用，而Zn2+、Ba2+、Ag+、Cu2+、Al3+、Fe2+、Fe3+、Hg2+、螯合剂EDTA、citrate则对该酶有不同程度的抑制作用，并且在Tween系列及TrintonX-100等非离子型表面活性剂中表现出较好的稳定性；酶的动力学参数Km为0.90 mg/mL. |
| 英文摘要 |
| By single factor experiments，the fermentation conditions for cold-adapted amylase production from Micrococcus antarcticus were determined as follows(medium g/L)：Na2HPO4 2.0，KH2PO4 1.0，MgSO4·7H2O 0.1，NaCl 5.0，(NH4)2SO4 2.5，maltose 5.0，trace element solution 5.0 mL，pH 8.0，100 mL/Erlenmeyer flask (500 mL)；cultivation was in a rotating shaker at 12℃ and 160 r/min for 64 h.Under those conditions，the highest total enzyme activity (2.6 U/mL) was obtained and increased by 10.8 fold compared with the original value of 0.24 U/mL before optimization.This amylase was purified by concentration with ultrafiltration membrane module，Hitrap Q anion exchange chromatography and Superdex 200 gel filtration chromatography.The optimal temperature and pH for the purified amylase were 30℃ and 6.0，respectively.It still showed high activity at low temperature 10-15℃.It was sensitive to high temperature but was stable at pH 6.0-10.0 with at least 70% activity remained.These results indicated that it was a typical cold-adapted enzyme.The enzyme activity was stimulated by Ca2+，Mn2+，Co2+ and Mg2+；but inhibited by Zn2+，Ba2+，Ag+，Cu2+，Al3+，Fe2+，Fe3+，Hg2+，EDTA and citrate.This cold-adapted amylase showed resistance to inactivation of 0.1% nonionic surfactants such as Tween 80，TrintonX-100，etc.Its Km was 0.90 mg/mL. |
