微杆菌XL1左聚糖酶的发酵条件优化及酶学性质研究Optimization of Fermentation Conditions and Enzymatic Properties of Microbacterium sp. XL1 Levanase
徐海洋,赵紫琰,陈倩倩,吴丹,张岩,霍东明,徐淋香
摘要(Abstract)：
为提高微杆菌XL1左聚糖酶的产量，采用单因素试验和响应面试验对微杆菌XL1的产酶发酵条件进行优化，并对左聚糖酶的酶学性质和水解产物进行分析。优化结果表明，微杆菌XL1的最佳产酶条件为左聚糖3.4 g/L,酵母粉3.8 g/L,FeSO_4·7H_2O 0.01 g/L,CaCl_2 0.1 g/L,KH_2PO_41 g/L,MgCl_2 0.15 g/L,初始pH值6.0,接种量4%,25℃、180 r/min培养30 h。在此条件下，微杆菌XL1发酵液酶活力达到3.47 U/mL,相比优化前提高了298%。酶学性质分析表明，左聚糖酶的最适反应温度为55℃,最适反应pH为5.5;在40～50℃、pH 5.0～7.0时酶活力较稳定；Co~(2+)、 Ca~(2+)和Mn~(2+)能显著提高酶活力；Cu~(2+)、 Ni~(2+)、 Zn~(2+)和EDTA对酶有较强的抑制作用；β-巯基乙醇和表面活性剂(Triton X100、Tween 80、SDS)对酶活力的影响较小。该左聚糖酶对左聚糖、菊粉和蔗糖均有水解活性，左聚糖和菊粉的最终水解产物为果糖。该左聚糖酶在生产高果糖浆上具有良好的应用潜力。
关键词(KeyWords)： 微杆菌;左聚糖酶;发酵优化;响应面;酶学性质
基金项目(Foundation): 江苏省高校自然科学基金面上项目(22KJB180015);; 江苏省博士后科研资助计划(2019K215);; 江苏省海洋资源开发研究院开放课题(JSIMR202111)
作者(Author): 徐海洋,赵紫琰,陈倩倩,吴丹,张岩,霍东明,徐淋香
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